:? I need an idiot's guide to this topic.

I'm building a new system and it took a while for me to pin down the memory, but I eventually decided on this:

http://www.crucial.com/store/MPart [...] IT6464Z40B

But, then I saw these two for only $15 USD more:

http://www.crucial.com/store/MPart [...] IT6464Z402

http://www.crucial.com/store/MPart [...] IT6464Z505

Is performance memory worth the extra money? I've read some sites which say it isn't because the only way to see a noticable difference is by benchmarking it. If performance memory is better, then which one should I choose? I am not a hardcore gamer, I am not looking to overclock, and this is going into a AMD s939 system.

if you are not going to overclock and you are not big into gaming then go with the last momery on your list "http://www.crucial.com/store/MPartspecs.Asp?mtbpoid=BF810D2AA5CA7304&a...WSMD=A8 " Its a doller more and a tad faster. You will be happy with it!

Think of performance modules as hand-picked value modules.
They cost roughly the same for the manufacturer, but they want to sell it for double or triple the price of a normal module!!!

Personally, I think its over-rated!!!
Getting big numbers in benchmarks is great but shows minimum actual real world performance bumps!!

Spend the money on getting more capacity in value RAM, 2GB and above, your system will run a lot more smoother!!!

But with only $15 being the difference.......get the CL2 modules!!!

I got the high prefromance modules XMS2 DDR2 Pro modules basically I now have the freedom to OC. (although my MB is holding me back now days)

I used to get generic crap elixar, cant do any oc with this stuff but it was dirt cheap.

I would never go back to crap ram again because I know that you are not getting the maximum preformance out of your system.... You can justifiy it like this "I spent a lot on my CPU, GPU, MB... why hold them back with crap ram.

You don't plan on overclocking? Then there's NO point for getting "performance" RAM.

In spite of what the RAM module's name/specs may suggest, no DDR module will actually, by default, run better than at an effective 400MHz rate, and will likely not run at a CAS latency of lower than 3.

In other words, if you plan on going with default settings anyway, you'd be defeating the whole point of getting "performance" RAM.

Note that even if you are tempted to overclock just a little, getting the performance RAM might not make much of a difference anyway; RAM modules actually tend to have little use for those "heat spreaders" (DDR, which typically is mad on a 130nm process now, really only needs those if you've overclocked them quite a bit, and your airflow's crap; DDR-2 is made on the 90nm process, and has no need of them whatsoever)

And "value" DDR is also overclockable, though it just tends not to be as much so. (I'm currently using a dirt-cheap RAM set that cost me <$80US, and I've got a rock-solid 11% overclock on them)

Lastly, in an Athlon64 system, it appears that the clock speed of the RAM tends to have little impact on gaming performance; since the memory controller (or two, in the case of all S-939 and S-AM2 chips) is located in the CPU itself, memory performance is actually enhanced by simply overclocking the CPU itself.

Personally, I don't see any reason to pull your hair over getting more expensive RAM. If you're simply looking for a decent (as well as reasonably-priced, I'll assume) gaming rig, then plain DDR modules are fine.

I think you should just spend the 15 bucks... i read articles about how from 3-2 the different in performance was from 5-15 percent... but i dont know... besides... its not like you dont have 15 bucks to spare??? perhaps maybe in the future you want to toy aroudn with your sys alittle bit... having a better ram can oc your sys to higher freq much more easily without crashing

Get those ones; they're worth the extra money.

http://www.crucial.com/store/MPart [...] ...WSMD=A8

These are rated @ DDR500 with a better CAS than those 100MHz inferior modules. Even if you don't want to overclock, you can lower the latencies (at DDR400 speeds) to make the most of your system.

"In spite of what the RAM module's name/specs may suggest, no DDR module will actually, by default, run better than at an effective 400MHz rate, and will likely not run at a CAS latency of lower than 3"

I don't know what you're talking about, since anything above 400MHz will run better than 400MHz (providing the latencies are not too laxed).
Bandwidth has proven to be much more effective than latencies for an increase in memory performance on the A64+ CPU's (ie. extra MHz > lower timings).

Also, socket 939 and AM2 do not have two memory controllers, but one dual-channel memory controller - as opposed to socket 754's single-channel memory controller.

Some months ago while Microsoft was explaining more details about Vista, I remember them commenting on system stability issues over the years, and their testing showing a lot of the problems were due to cheap RAM. So they were considering requiring ECC for Vista. So just in case I'm sticking with the name brands like Corsair. You can get good timings and decent prices if you avoid the hyped up modules with the bling like LED's.

I had the blinking leds on my RAM because the normal non pro version of XMS2 wasnt in stock and I had about 2.5k worth of PC parts sitting in my room doin nuffink... slowly depreciating day by day and I was just itching to play some games again. The blinking leds are not worth it I agree but you wait 3 weeks for your ram modules and see how you feel.