- Количество слайдов: 47
Chapter 3 Processing Maran Illustrated Computers CIS 102
Content • • Memory CPU Memory Cache Bus
Matched processor and RAM ratings Processor Model Front Side Bus DDR, DDR 2 or DDR 3 rating Memory channels T 5200, T 5300, U 7 n 00 533 MT/s PC 2 -4200 (DDR 2 -533) Single channel 4. 267 GB/s T 5 n 00, T 5 n 50, T 7 n 00, L 7200, 667 MT/s L 7400 PC 2 -5300 (DDR 2 -667) Single channel 5. 333 GB/s PC 3200 (DDR 400) or PC 23200 (DDR 2 -400) Dual channel 6. 400 GB/s PC 2 -6400 (DDR 2 -800) Single channel 6. 400 GB/s Dual channel 8. 533 GB/s PC 2 -8500 (DDR 2 -1066) Single channel 8. 533 GB/s PC 3 -8500 (DDR 3 -1066) Single channel 8. 533 GB/s PC 2 -5300 (DDR 2 -667) Dual channel 10. 667 GB/s PC 3 -10600 (DDR 3 -1333) Single channel 10. 667 GB/s T 5 n 70, Socket P T 7 n 00, L 7300, L 7500, X 7 n 00 800 MT/s E 4 n 00/Pentium E 21 n 0/Celeron 800 MT/s 4 n 0 E 6 n 00, E 6 n 20, X 6 n 00, Q 6 n 00 1066 MT/s PC 2 -4200 (DDR 2 -533) and QX 6 n 00 E 6 n 40, E 6 n 50, QX 6 n 50 1333 MT/s Bandwidth
Why doesn't my Windows® PC recognize the whole 4 GB of memory I installed? The maximum amount of memory that your system can use is actually limited in two ways — not only is there a maximum amount of memory that your computer motherboard can accept, there is also a maximum amount of memory that your operating system (OS) can accept. For instance, when you install 4 GB of memory in a 32 -bit Windows system (the most common version; 64 -bit systems are typically used only by high-end users), your system will see (and utilize) only 3 GB or 3. 5 GB. Is the problem bad memory? Relax, there isn't a problem with the memory. Windows allows for 4 GB of memory to be addressed, but this isn't 100 percent the same as having 4 GB of physical memory. What happens is that some of the addressable memory (regardless of how much you have physically installed) is reserved for use by page files or by some of the devices that you are using, such as a graphics card, PCI card, integrated network connections, etc. , so it's unavailable for use as normal main memory. The amount of memory needed for these devices is calculated by your system at startup; if you haven't maxed out the memory in your system, it's invisible to you, and all your physical memory (the RAM that's installed) is available for use. However if you've maxed out the DRAM in your system, this amount will be deducted from your physical memory, so you can't use 100% of your DRAM.
The maximum memory limitation varies by operating system; for instance, the 4 GB memory limitation doesn't exist in 64 -bit versions of Windows. Memory maximums for current Microsoft® Windows OSs include: Windows XP Home: 4 GB Windows XP Professional: 4 GB Windows XP 32 -bit: 4 GB Windows XP 64 -bit: 128 GB Windows Vista Home Basic: 4 GB Windows Vista Home Basic 64 -bit: 8 GB Windows Vista Home Premium: 4 GB Windows Vista Home Premium 64 -bit: 16 GB Windows Vista Ultimate: 4 GB Windows Vista Ultimate 64 -bit: 128 GB+ Windows Vista 32 -bit: 4 GB Windows Vista 64 -bit: 128 GB+
The next two slides are from a technical post by a homebrew artist I've spent a lot of time on this issue over the last 6 months or so. I have things working for the most part. Here are some of the facts I've been able to collect during my troubleshooting: 1) Of course, 32 -bit operating systems won't recognize more than 2. 75 - 3. 25 GB RAM - you have no choice but to upgrade to a 64 -bit O/S. 2) Motherboards older than about a year are a toss-up as to whether they'll work with 4 GB RAM or not. Some will, some won't. Higher-end boards do better than entry-level or mid-range boards. It has more to do with how the motherboard has been designed and what the BIOS does than it has to do with Microsoft's programming. There are similar issues with Linux operating systems. 3) Anything above 3 GB RAM conflicts with the PCI-Express video card memory address space. That's the way boards have been designed for years to make everything compatible. If your motherboard/BIOS supports memory remapping, then you have a good chance at making this work. If it doesn't, don't look for software patches - there's not much you can do. The PAE switches for Windows are very, very unlikely to work! Buy a new motherboard (sorry). If your BIOS doesn't count to 4 GB, then you might as well stop there - again, no software patches will fix the way your motherboard and BIOS have been designed.
4) Most motherboards (except the higher-end ones) don't work well with all 4 memory slots populated. Most often, you have to bump down the speed of the memory. For example, if you are using DDR 2 -800 memory (which is still considered an overclock for a lot of the motherboards out there), you have to bump it down to DDR 2 -667 or even DDR 2 -533. If you want to run at a higher speed with all 4 slots populated, buy a new, expensive motherboard (sorry again). 5) If you're running 4 GB RAM and have an n. Vidia SLI video card configuration (prior to the 8600/8800 series), you're going to have problems. There seems to be a conflict (remembering that video card address space conflicts with the 4 GB RAM range). This does appear to be fix-able via n. Vidia driver updates. I finally got this working by using a little-advertised n. Vidia beta driver version 160. 03. Guru 3 D has this driver, but n. Vidia doesn't advertise it at all. Eventually, I expect that the upcoming n. Vidia drivers will fix these problems. I have had success with the e. VGA 680 i motherboard with 4 GB RAM (OCZ Platinum 4 x 1 GB DDR 2 -800). I can also get the ASUS P 5 N-E SLI board to work IF I underclock the memory to 667 MHz. Generally, nobody wants to admit they are having some serious problems with 4 GB RAM - it seems that nobody was expecting so many people to upgrade to 4 GB RAM so early, but with Vista. . . it's becoming a requirement for any enthusiasts. You won't likely see motherboard manufacturers admit that their boards won't handle 4 GB RAM - they'll blame it on MS or on the type of memory you have, but in my experience, it's always the board and its BIOS.
Virtual memory is a common part of most operating systems on desktop computers. It has become so common because it provides a big benefit for users at a very low cost. For example, most computers today have something like 512 megabytes to 2 gigabytes of RAM available for the CPU to use. Unfortunately, that amount of RAM is not enough to run all of the programs that many users expect to run at the same time. If a user loads the operating system, an e-mail program, a Web browser, a word processor, five sessions of the Internet, and a Direct. X 9 game into RAM simultaneously, 512 megabytes may not be enough to hold it all. If there were no such thing as virtual memory, then once you filled up the available RAM your computer would have to say, "Sorry, you can not load any more applications. Please close another application to load a new one. " With virtual memory, what the computer can do is look at RAM for areas that have not been used recently and copy them onto the hard disk. This frees up space in RAM to load the new application.
Because this copying happens automatically, you don't even know it is happening, and it makes your computer feel like is has unlimited RAM space even though it only has 512 megabytes installed. Because hard disk space is so much cheaper than RAM chips, it also has a nice economic benefit. The read/write speed of a hard drive is much slower than RAM, and the technology of a hard drive is not geared toward accessing small pieces of data at a time. If your system has to rely too heavily on virtual memory, you will notice a significant performance drop. The key is to have enough RAM to handle everything you tend to work on simultaneously -- then, the only time you "feel" the slowness of virtual memory is when there's a slight pause when you're changing tasks. When that's the case, virtual memory is perfect
When it is not the case, the operating system has to constantly swap information back and forth between RAM and the hard disk. This is called thrashing, and it can make your computer feel incredibly slow. The area of the hard disk that stores the RAM image is called a page file. It holds pages of RAM on the hard disk, and the operating system moves data back and forth between the page file and RAM. On a Windows machine, page files have a. SWP extension.
Choose a CPU
Processor Competitive Comparison AMD Athlon™ 64 X 2 and AMD Athlon™ X 2 Dual. Core Processors Infrastructure AMD Athlon™ 64 X 2 and AMD Athlon™ X 2 Intel Core 2 Dual-Core Processor Duo Processor socket AM 2 Socket LGA 775 Process Technology 90 nanometer, SOI (silicon on insulator) 65 nanometer Number of Transistors 90 nm: 164 to 243 million (depending on cache size) 65 nm: 221 million 291 million 64 -bit Instruction Set Support Yes, AMD 64 Technology Yes, EM 64 T Yes, Execute Disable Bit Enhanced Virus Protection* System Bus Technology Hyper. Transport™ technology up to 2000 MHz, Front Side Bus up full duplex to 1066 MHz, Half duplex Integrated Memory Controller 128 -bit + 16 -bit ECC unbuffered PC 2 No, Discrete logic 6400(DDR 2 -800), PC 2 5300(DDR 2 -667), PC 2 device on 4200(DDR 2 -533), PC 2 3200(DDR 2 -400) motherboard Total Processor-to. System Bandwidth Hyper. Transport technology: up to 8. 0 GB/s Memory bandwidth: up to 12. 8 GB/s Total: up to 20. 8 GB/s Total: up to 17. 0 GB/s 3 D & Multimedia instructions Chipset support Total Designed Power (TDP) 3 DNow!™ technology, SSE 2, SSE 3 SSE, SSE 2, SSE 3 NVIDIA: Nforce Series chipsets ATI: Radeon Xpress Series chipsets VIA: K 8 Series chipsets Si. S: 75 x Series chipsets or greater Intel: 975, 965, 963, 946 NVIDIA: Nforce Series chipsets 45 W, 65 W, 89 W, or 125 W 65 W or 95 W
Intel Pentium 4
Intel Pentium 4 with HT Technology
Intel Pentium 4 Extreme Edition with HT Technology
This is the link to the Intel CPU part numbering page for the Core 2 Duo processors http: //www. intel. com/products/processor _number/chart/core 2 duo. htm
AMD Athlon™ XP
AMD Athlon™ 64
AMD Athlon™ 64 FX
shorter, until you get to the Opteron (server) series. http: //products. amd. com/enus/Desktop. CPUSide. By. Side. aspx? id=69 &id=70
Using Memory Cache
L 1 Cache
L 2 Cache
L 3 Cache
Bus width, speed and bandwidth
Comparing Bus Types