Home > Articles > Hardware > Upgrading & Repairing

This chapter is from the book

Types of Memory

Memory chips are soldered to small circuit boards to form a package called a memory module. In the old days, before memory chips were soldered to modules as shown in Figure 6.1, you had to install each individual chip onto the motherboard. Today, memory modules make memory upgrades easy.

Figure 6.1Figure 6.1 Memory "chips" are mounted onto memory modules.

The size and shape of the module, as well as other characteristics, make up its form factor. Starting from the top of Figure 6.2, each memory module's form factor is described below. In the next few sections, you'll use these illustrations to identify the type of memory your system has.

Figure 6.2Figure 6.2 Types of memory modules. From top: 72-pin SIMM, 168-pin DIMM, 184-pin DDR DIMM, 184-pin RIMM.

  • 72-pin SIMM (single inline memory module). This is an older style module that was used on early Pavilions (series 50xx, 51xx, 52xx, 53xx, 70xx, 71xx, 72xx, 73xx, 74xx, 81xx).

  • 168-pin DIMM (dual inline memory module). This is the most common memory module on HP Pavilions. It was used extensively on models from 1997 to the present.

  • 184-pin DDR DIMM (double-data rate DIMM). This module uses a form factor similar to the DIMM and is often confused for standard DIMMs, but the memory chips are capable of transferring data at double the data rate of traditional DIMMs.

  • 184-pin RIMM (Rambus inline memory module). This is a special memory type developed by Rambus that Intel tried to popularize. It works with Intel Pentium 4 processors, but is used on only two of HP's motherboards at this writing.

One of the differences between the older style SIMM and the new DIMM and RIMM formats is the mounting technique. I mention this so you can identify what your system has. Figure 6.3 shows the 72-pin SIMM socket. There is a small metal clip at each end that holds the SIMM in place. You push the clip outward and then tilt the SIMM out of the socket, as shown. Compare this to the DIMM slot shown in Figure 6.4. When a DIMM is pushed into place, the hammer-type lock engages the notch on the side of the DIMM. To remove a DIMM, you push down and outward on the locks at both ends, which pushes the DIMM out of its socket. Installation and removal methods are discussed later.

Figure 6.3Figure 6.3 SIMM slot with metal mounting clip.


Figure 6.4Figure 6.4 DIMM slot with hammer-type locks.

Note the other identifying characteristics of the different memory modules. There are small notches near the metal contacts at the bottom of the modules. These are "keys" that ensure the module is inserted correctly and that only the right type of module is inserted in a memory socket.

Interesting Memory Characteristics

PC memory has gone through a lot of changes over the last 20 years. As mentioned, in the early days, you had to push each individual chip into the motherboard. Now that they are mounted on small circuit boards, installation is much easier and you don't need to hire a technician to install your memory.

The biggest change in PC memory occurred in 1997 when Intel created synchronous dynamic RAM, or SDRAM. SDRAM is synchronized with the CPU so that data transfers can be more efficiently coordinated. A side benefit is that memory speeds could be increased dramatically. Almost all memory for PCs is a form of SDRAM. The packaging (form factor) is what differs—and of course the speed and access methods.

The new SDRAMs were placed on a circuit board with 168 pins, and the entire package was called a DIMM (dual inline memory module). DIMMs use a 64-bit data path to the CPU as compared to the 32-bit data path of the older SIMMs. Most were designed to work in the early Pentium-class system, which had a 66 MHz CPU bus. The memory specification for these systems was called PC66. Later, Intel developed the PC100 specification, which defines a 100 MHz CPU-to-memory bus. Later, this bus was increased to 133 MHz and the PC133 memory specification was defined.

If you look through Table 6.1 in the next section, you'll see a variety of speeds for memory. This is the speed at which data transfers across the CPU-memory bus (front side bus). New types of memory called double-data rate (DDR) SDRAM and Rambus DRAM or RDRAM have emerged to improve the data transfer rate.

DDR memory doubles the amount of data that is sent during each clock cycle. So if it is attached to a 100 MHz bus, DDR memory essentially transfers data at 200 MHz (100 x 2). On a 133 MHz bus, DDR memory transfers at 266 MHz (133 x 2). Below is a list of standard and DDR memory types that are used in current Pavilion models. Other memory types are available, but they are not used in Pavilion models.

  • PC66. This is standard 66 MHz SDRAM on a DIMM-format memory module.

  • PC100. Standard 100 MHz SDRAM on a DIMM-format memory module. The motherboard and CPU must support a 100 MHz CPU-memory bus.

  • PC133. Standard 133 MHz SDRAM on a DIMM-format memory module. The motherboard and CPU must support a 133 MHz CPU-memory bus.

  • DDR 200. This memory implements double data rate transfers on a 100 MHz bus. Also called PC1600 because it transfers 1,600 MB/sec.

  • DDR 266. This memory implements double data rate transfers on a 133 MHz bus. Also called PC2100 because it transfers 2,100 MB/sec.

RDRAM is a high-performance memory technology developed by Rambus Corporation and adopted by Intel. At one point, Intel was trying to move the entire market to adopt RDRAM and its licensing agreements, but DDR memory leaped ahead in performance and cost savings. Only two HP Pavilion motherboards support RDRAM, while most new boards support DDR memory. RDRAM is described later in this chapter.

Tips and Techniques

Here are few things to know about memory if you are going to upgrade your system.

  • Some motherboard support multiple CPU bus (front side bus) speeds such as 66/100 MHz or 100/133 MHz. The CPU installed will determine at what speed this bus runs. If a Celeron CPU is installed with a 66 MHz CPU bus, PC66 memory modules should be installed. If a CPU with a 100 MHz front side bus is supported, then use PC100 memory. Likewise, if a CPU with a 133 MHz front side bus is supported, then use PC133 memory.

  • Some HP Pavilions have integrated video graphics controllers that use part of RAM for video memory. By upgrading memory, you're also able to expand video memory, which means you can use higher resolutions and more colors. This is discussed in the next chapter.

  • You are wasting money if you buy a low-capacity memory module and then need to expand in the future. Remember, there are only two or three memory slots. To expand, you might need to remove a module in a slot to make way for a higher capacity module.

  • Recycle your memory modules by moving them to another computer that needs a boost, or give them to someone who will really appreciate them.

  • If you have two DIMM modules with different memory sizes, put the largest module in the first slot.

  • Never mix modules of different speeds (i.e., don't mix 100 MHz and 133 MHz modules).

  • If you have problems after installing memory, make sure the module is properly seated and check the contacts for dirt.

  • If you are not sure whether your system supports 100 MHz or 133 MHz DIMMs, go ahead and get the faster DIMMs. They cost just a little more, and will run on a 100 MHz CPU bus. And you'll have the faster DIMMs to put in a new motherboard if necessary.

  • If you have problems after installing a module, it may be defective or it may not work with an existing module. Try removing it and see if your system still starts with the original module, then try starting with just the new module. You can also try switching the slot locations of the modules.

  • Motherboards that use the Intel 430 series chipsets have a caching problem when over 64 MB of memory is installed. If you have a 31xx, 32xx, 5030, 5040, 5120, 5215, 5250, 5315, 5315D, 5320, 7010, 7020, 7030, 7050, 7070, 7090, 7055, 7110Z, 7125, 7130P, 7145, 7160, 7170, 7222, 7260, 7275, 7310, 8140, 8160, 8201, 8240, 8242, or 8246 model, don't install more than 64 MB of memory.

  • In systems that use the Type 1 case, the height of the DIMM modules must not exceed 1 inch. Taller modules will not clear the drive bay when the motherboard panel is swung back into place. In fact, you practically have to wedge the motherboard into the case even with the right size of DIMM.

  • Windows 98 may run slowly on systems with over 512 MB of memory. Search the Microsoft Knowledge Base for Q253912 to learn more about this problem if you plan on installing that much memory and running Windows 98.

  • You can buy memory from the big names like PNY (http://www.pny.com) and Crucial (http://www.crucial.com), or you can check prices with a whole group of memory vendors at Price Watch (http://www.pricewatch.com).

NOTE

Hewlett-Packard tests memory from various vendors for compatibility in its systems. It recommends you use only memory that it has tested and approved. While other memory will work, HP may ask you to pull the memory before it will provide any warranty service.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020