Questions about Corsair TWIN2X4096 800Mhz and memory speed in general

[kallekill]

I'm going to buy a Intel Q6600 CPU when the prices go down and I'm trying to decide which memory I'm going to pair it with. I am aiming to overclock the Q6600 from the default bus speed of 266 to 333 to get the CPU to 3 Ghz. I am leaning towards buying the Corsair TWIN2X4096-6400C5DHX 800MHz since I think it will be enough for my needs.

I am a bit rusty at memory speed and timings, but if I understand this correctly, a FSB of 266 Mhz means the memory is running at 532 Mhz. At a FSB of 333 Mhz the memory is running at 666 Mhz which is no problem for the Corsair 800 Mhz. This means that I can use a CPU/Memory ratio of 4:5 and run the memory at 832 Mhz. Can the Corsair TWIN2X4096 handle this frequency? It should be a problem since it isn't that much above the specs, right? It will also leave me some room if I decide to go for a higher overclock with a 1:1 CPU/Memory divider.

Also, does a 4:5 CPU/Memory ratio show any real world performance gains? The overclocking guides I've been reading say that you should choose a 1:1 ratio.

My third question is how well the Corsair TWIN2X4096 will perform. It is rated at 5-5-5-18 which seems a bit high. How much will this affect the performance of my computer?

 

[JustaGeek]

These two threads should help you understand the issues of 4GB RAM and the timings.

http://forums.anandtech.com/me...=2068758&enterthread=y

http://forums.anandtech.com/me...070500&highlight_key=y

And another one about more than 3GB of RAM:

http://www.dansdata.com/askdan00015.htm

 

[kallekill]

Originally posted by: JustaGeek
These two threads should help you understand the issues of 4GB RAM and the timings.

http://forums.anandtech.com/me...=2068758&enterthread=y

http://forums.anandtech.com/me...070500&highlight_key=y

And another one about more than 3GB of RAM:

http://www.dansdata.com/askdan00015.htm

After reading those threads I am still wondering how bad a memory rated 5-5-5-18 will affect the performance of my computer. I am especially worried about the 18 at the end which seems rather high. Also the memory was pretty cheap, which makes me suspect that it will perform badly.

How much will I be able to lower these setting? Is it probable that I will be able to lower these settings to say 4-4-4-12 just like it is probable that an Intel Core 2 Duo 2 GHz CPU will overclock to 3 GHz?

 

[JustaGeek]

I do not think that you will be able to lower the timings in memory modules as dense as 2GB. If you want performance, and still want 4GB of RAM, go with 4x1GB, 4-4-4-12 or better.

It will also be much less expensive, probably ~$150 for 2 pairs of "medium quality", ~$250 for the memory with Micron chips. I do not know why you are saying it was "pretty cheap" - it is ~$330 AR on Newegg.

And 5-5-5-18 at 800MHz will be probably outperformed by 4-4-4-12 at 667MHz.

Well, you are the only one who can decide what quantity and performance of memory you require for your applications.

 

[kallekill]

I compared the prices of the Corsair 2*2GB modules and the Corsair 4*1GB modules with the same performance and it wasn't that much of a difference. 2*2Gb costs 323.89 USD and 4*1GB costs 302.35 USD. I live in Sweden so I converted the price from Swedish kronor. I thought 2*2GB was better if I would like to upgrade with more memory some time in the future, but I didn't take into account that it could be easier to lower the timings on the 4*1GB modules. I'm now considering buying two of these instead: Corsair XMS2-6400 TWIN2X2048-6400C4 4-4-4-12 Xtreme which cost 165.26 USD a piece. I won't be able to add more memory later though.

I see you are running 4-4-4-12 memory. Have you lowered the timings on those?

 

[JustaGeek]

My memory was rated for 4-4-4-12, and I had to set it manually in BIOS.

"Denser" modules like 2GB have trouble running at lower latencies, that's why I would recommend 1 GB modules.

Again, if these 2GB modules are rated 5-5-5-18, I seriously doubt you'll be able to do better than that...