RAM For Conroe, PC6400 OK? Latencys?

[slim142]

Hi

I have been reading topics about ram for conroe and I dont want you guys to be writing me the same thing as others because it would be a waste of time so here are my questions.

Im planning to get PC6400 (800mhz) since I dont want PC5400 (667mhz). Now I have checked many PC6400 Ram memories and most of them have CAS 5. And as I was reading the topics here you guys recommend CAS 3 because is faster ( I dont know about ram memory so im kinda noob at this)

So my question. Why should I buy CAS 3 (As I dont understand what is CAS for or what it means) instead of CAS 5? And do you guys know of any 512X2 pair of a good brand? Because the only kit I found on newegg was a Corsair of 240$ and thats expensive. Tigerdirect only has CAS5. So any recommendations?

ADDED: I cannot find any DDR2 PC6400 with CAS Latency of 3. And CAS Latency of 4 are very few and only by overclocking (example: Kingston).
I need help I want a good PC6400 but If I cant afford a good CAS Latency of 3 or 4 then Ill have to get CAS 5 which I know wont be bad but it would be better to get Cas 3 or 4.

 

[derek2006]

Read this and this. These will help u decide u probly dont need expensive ddr2 6400.

 

[slim142]

I still thinking about just gettin PC6400 with CAS 5. I would not like to buy anything lower.

Thanks anyways for the topic help.

 

[tmac]

I still thinking about just gettin PC6400 with CAS 5. I would not like to buy anything lower.

Thanks anyways for the topic help.

Corsair has a CAS3:

CORSAIR XMS2 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400)
Unbuffered Dual Channel Kit System Memory Model TWIN2X2048-6400C3
Cas Latency: 3
Heat Spreader: Yes
Timing: 3-4-3-9

Though I think they tweak the voltage to get these results.

The motherboard I'm thinging about getting is the one with ATI's
RD600 chipset. DFI is making them.

http://www.xtremesystems.org/forums/showthread.php?t=101642&page=2

Exerp from the above link.

The most notable feature of the RD600 is the memory controller. ATI has developed an elaborate memory controller that operates asynchronously from the front-side bus. No more memory dividers means the front-side bus can be overclocked drastically without being limited to memory. There will also be support for DDR2-1066 too. ATI claims the RD600 has been overclocked to 375 MHz (1500 MHz Quad pumped) using the current reference board.

Is the RD600 chipset, only making overclocking easier for the memory?
But you are still limited to the bandwidth of the FSB?

 

[slim142]

yeah but what about THE PRICE?

$260 on newegg. I think thats the lowest price in the web.

I dont think I need 2gb. Im not even gonna spend $260 JUST on memory. Im looking for 1Gb for about $100.

 

[wolfman140]

Tom's has an article somewhere here about the results of lower ram timings. Basically, the faster (Mhz) speed of the RAM, the CAS latencies/timings are going to go higher...It's just the nature of the beast. Lower Mhz RAM will have quicker timings. When it came to comparing fast ram/high timings to slower ram/low timings, the difference was almost negligible. The performance increase was not enough to justify the price of more expensive/faster RAM. This is sort of the reason why AMD has stuck with just DDR(1) for so long before moving to DDR2. If you've got cash to burn (which it sounds like you don't) get the Corsaire with tight timings someone already mentioned. If not, get the slower ram with lower timings.

 

[slim142]

Ill try I promise Ill try to afford to get the Corsair one but if in case I cant I have THINK once again and I think you are right. You two guys are right I should not consider faster ram but faster timings. And DDR5400 has some good timings at 667mhz.

Ill see if I can afford the corsair anyways

PD: The corsair one is not like the kingtons ones right? because the kingstons DDR6400 with CAS 3 are originally CAS 5 but can get overclcoked to CAS 3. Im not thinking to overclock my system no matter what.

 

[RichPLS]

From Crashman: I seem to be the only one here who cares, but I'm going to tell you something that most other people simply refuse to believe: Synchronous RAM for the 1066MHz bus is DDR2-533, aka PC2-4200, ie, the slow stuff.

But wait you say, that's only half as fast? Nonsense. 1066MHz FSB runs at a 266MHz clock rate. DDR2-533 runs at a 266MHz clock rate. But wait you say, it's still only half the bandwidth because of Intel's Quad Data Rate FSB? Nonsense, that's what dual-channel is made to fix.

So why do higher-speed modules win benchmarks? Latency. Think about it, using DDR2-800 CAS4 as an example: a 400MHz cycle is 2.5ns, so that CAS4 has a latency of 10ns. If you compare that to DDR2-533 CAS3, well, the same math says its over 11ns. That sounds small right? The difference in benchmarks isn't that big either, 200 3D Marks is only 3% of 6000 3D marks.

So quit worrying about 1066MHz and start worrying about latency. Corsair has some PC2-6400 CAS3 you might like.

 

[derek2006]

We should make crashmans post a stickie or something. How many people have asked the question about what ram they should use for conroe just this week. I think it was like 8+ people. Hey also if you clicked on my link it would of taking u to that thread.