I am so confused about RAM

[bonanza2000]

I am so confused about RAM. For example looking at 2 Corsair XMS3 - 4GB Duel Channel kits which is better and does it really matter? Both are $50

CMX4GX3M2A1333C8 or CMX4GX3M2A1600C9

The first one is 1333 Mhz and second is 1600 MHz and higher is better right? But the first has a latency of 8 and the second of 9 and lower is better right? So which do you buy? And could you even tell a difference between them?

Anyone? Rules of thumb? General guidelines?


And while I am at it, 1.5V or 1.65V - does it really matter and if so when does it matter? Looking at the recommended memory for the motherboard they list both voltages, so I am confused.

[audirs]

typically the higher the mhz freq, the slower the cas latency gets. you will find high performance ram with low cas and high freq. id opt for the 1600mhz personally, strickly for gaming you wont notice much of a difference between the 2, but you could get some better overclocking headroom with the 1600mhz dimms

[ilya]

With the current speeds of DDR3 RAM, timings are a moot point. Get the higher clocked set if the price difference is negligible. (which it usually is)

With regards to overclocking headroom, it's an even bigger hit and miss than with CPU overclocking. A 1333 set could clock much much higher than a 1600 set, if you're lucky. The only difference between the sets is that the 1600 is guaranteed to run at 1600.

I would personally go for the lower voltage set. DRAM voltage must be within 0.5V of QPI/VTT for i7 processors. (I'm assuming it's for your build in system specs) That value is typically 1.1 or 1.2 at stock, not accounting for vdroop or other voltage fluctuations. With a 1.65v kit and no added QPI/VTT voltage, you may have stability issues. Of course you could pump up your QPI/VTT to avoid this though. However, I don't see the point, unless you're overclocking and already needed to increase that voltage.

[zsamz_]

ncix has 4gb 2000mhz patriot ram for 45$ after mir
buy it and be happy

[Mars]

Keep in mind that latency numbers refer to cycles, which become shorter as you increase the frequency.

So, 800 MHz memory with a CAS latency of 4 has the exact same CAS latency (time-wise) as 1600 MHz memory with a CAS latency of 8. (More or less, CAS latency doesn't really tell you much on its own, and overall latency of memory becomes somewhat technical.)

[bonanza2000]

thanks for the answers. I ended up buying some of the corsair 1600 xms3 ram for 50 and then a 15% discount from newegg on top of that. I guess as long as it works i'll be fine.

[pauladams]

So finally you own one RAM, what are your opinions about its working. Is it really worthy.