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Originally Posted by TheN00b
Just out of curiousity, what makes one kind of RAM better than another, besides megabites?
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Speed, timings and overclockability. Speed (like DDR400, aka PC3200) dictate how fast the RAM sends/recieves data. PC3200 RAM moves data at 3.2 gigs per second. (hence the 3200 in the name.) It is also called DDR400 because its memory chips run at 400mhz (well, not really, they run at 200mhz, but that value is multiplied times two, because it is Double Data Rate (DDR) Ram.) Most computers are only really technically compatible with DDR400 because no CPUs communicate at more than a base amount of 200mhz. Thus, if you got DDR500 memory, which runs at 250mhz (x2), and your CPU only runs at 200mhz (x whatever, like mine runs at x10 for 2000mhz) you would need to OC your CPU in order to get the most out of your RAM. (Otherwise your RAM would only be running as fast as your CPU.) This is why, if you don't want to OC, get DDR400 (assuming your CPU runs at 200mhz base speed).
Timings dictate how quickly the RAM is opened and closed (amoung other things). Quicker timings allow your CPU to switch from reading to writing and the like faster. Probably the most important timing value is CAS. When you see something like (2.5-4-4-6), CAS is the first number, in the case of my example, 2.5. This number dictates the RAM's basic latency in opening and closing. The other values are somewhat important too, but I won't go into them right now. Generally, the lower the timings, the better the RAM performs (lower latency is definately good). One last thing. Timings have more of an impact on performance if you are running an AMD system than if you are running an Intel. The RAM mentioned above doesn't have the BEST timings (still not bad) but if you are running an AMD, u might want to look for getting the best timings you can (which is expensive unfortunately).
Lastly, overclockability. Some RAM overclocks better than others. Expensive stuff built for gaming is usually the best at OCing, you can usually get them to operate at a dozen or so mhz faster than it is built to run at. It usually depends on the chips. Sometimes you may need to up the voltage to your RAM to get it to overclock. Some RAM chips are fine with this, others will not react in good ways (may overheat get fried, or have a shortened life span). Stuff like Winbond BH-5 RAM chips OC really well at low voltages (which is good, because u are unlikely to damage it). However that stuff is no longer in production. CH-5 chips can also OC well, but require tons of voltage, usually more than your BIOS will allow (many people manually modify their mobos to up the voltage, a dangerous process.) If you are interested in OCing your RAM, find out what chips your RAM manufacturer uses (usually Winbond, Hynix or Samsung) and find out what its capabilites are (sites like guru3d.com or amdmb.com are good sites to ask around about this). Remember tho, you can only OC your RAM up to the capabilites of your CPU. No sense in pushing your RAM up to 230 mhz when your CPU is running at 200. (Well not that I know of at least... I'm still a little shady on some of the finer points concerning what CPU:RAM dividers work best. As far as I know, 1:1 works best, which is having your CPU and RAM running at the same speeds.)
Hope that helps a little. RAM is a lot more complicated than many people think. I see SO many people just go out and buy a gig of RAM, with little attention to how fast it is, how good its timings are, or how well it OCs (which, when your RAM starts to get outdated, can be handy). Also, make sure you get 2 sticks of RAM to run in Dual-channel if you can. Dual channel allows your computer to access data from RAM very quickly (using the sticks in parallel, much like running hard drives in RAID if I'm not mistaken). Dual channel makes a bigger difference on Intels however than it does on AMD, and some CPUs (like my AMD 64) arent even capable of running RAM in dual channel
(at least its an AMD, so its not as drastic of a performance decrease as it would be on an Intel). Like I mentioned before, sites like guru3d.com and amdmb.com can be very helpful to picking your RAM. Head onto a memory forum and poke around a little. If you don't find anything helpful, start a thread, post your system specs, your budget, whether or not you want to OC, and ask about what RAM would work best with you. Lots of people will be happy to help out.
::End RAM INFO 101::
