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Remember The Memory!

Best Of Tom’s Hardware: How To Build A PC
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The easy solution to any memory debate concerning the latest processors might sound simple: just buy 1.5 volt DDR3-1066 (PC3-8500). All Socket AM3, LGA 1156, and LGA 1366 processors are designed to support at least this memory speed. It's inexpensive as both 1GB and 2GB sticks and its available in both dual-channel and triple-channel kits. Yet there are small performance benefits for similarly-priced DDR3-1333 (PC3-10600), and this speed functions normally, even with processors that are not officially designated to use it (mostly early-model Core i7 processors based on the Bloomfield design, for example).

Moving up to DDR3-1600 (PC3-12800) requires a little more consideration. First of all, many DDR3-1600 modules require a nonstandard 1.65V BIOS setting or higher (up to 1.9V) simply to run at its rated speed. Most boards will automatically select 1.5V, which is why many modules are detected at a slower speed determined by the manufacturer to be stable at the lower voltage. This explains why neophytes have been seen rushing, upset, to the Tom’s Hardware Forums when their DDR3-1600 modules are detected as DDR3-1333 or DDR3-1066.

Intel XMP (Extreme Memory Profiles) and EPP 2.0 (Enhanced Performance Profiles) are competing technologies that add overclocking data to the automatic-detection ROM, telling certain motherboards exactly how to overclock some models of performance memory. The use of overclocking profiles still requires the builder to enter the BIOS and manually select the profile they want their motherboard to use, and the use of XMP or EPP 2.0 profiles often overclocks other parts of the system, too.

Memory faster than DDR3-1600 is usually expensive and not really required. Our tests have shown that faster memory doesn’t add noticeably to the performance of applications, and even overclockers can reach the limits of their other components without exceeding DDR3-1600 data rates by simply using a lower DRAM multiplier.

But what about low-cost systems that still use dated DDR2 memory? PC2-5300 (DDR2-667) is so common that 1GB modules can be found for as little as $25. Because it's so cheap, there's no need to choose slower PC2-4200 in any new system build, even if the processor runs at a slower bus speed. You might even do better and find DDR2-800 for the same price.

In terms of memory quantity, Tom's Hardware recommends at least 1GB for the cheapest single-task 32-bit Windows systems. Users with a 64-bit version of Windows should have at least 2GB for light tasks and 4GB for regular use of 64-bit programs or heavy multitasking. Users who run multiple memory-intensive programs simultaneously can usually live with 8GB, and those who need more than 8GB are probably completely aware of their needs already.

Our memory reviews show a wide range of options, and buying name-brand modules with lifetime warranties from reputable venders is good insurance against "unexplained" system instability.

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