Hello.

I'm trying to figure out what CPU/RAM to buy that I can specifically overclock the CPU? I need 8GB (4-2GB Sticks) for 3D Rendering and I need a fast CPU.

I first tried to oc my Q6600 with PC2-6400 RAM but I can only get to 3.0GHz stable. If I use 2GBs of ram I can go to 3.6ghz.

What I'm looking for is the perfect RAM/CPU combo keeping in mind I want to overclock CPU with 8GB RAM? (should I be looking at PC2-8800 DDR2 ram so I don't have to oc the RAM?

What do you guys recommend?

I didn't think ram amount limited the amount of OC... I thought the number of dims limited the amount of OC

your PC2 6400 ram will run default speed with the cpu @ 3.6. Its not recommended to OC extreme with more the 2 sticks of ram. The more sticks you add the more voltage you need. With 2 sticks of 2g you usually are at the manufacturers maximum specs. YOu might get it done but you will need Highend , PSU and Ram.

If I remember correctly there is no desktop chipset that supports 4GB DIMMs, so make sure you find a motherboard that will actually support 2x4GB DIMMs before you buy them.

Try to feed the chipset a bit more voltage. 4 sticks up more strain on the memory system.

I have 4 2GB sticks in mine with the 680i and Q660@3.4. Works just fine. You have to make sure you set the RAM voltage correctly. MY MB puts the ram at 1.8 and that will not get me stable with an OC. I put it at 2.0 as that is what it is spose to run at. Been running stable for almost 6 months now.(Its build date.)

I have the X3350 (Q9450) at 3.4 (425X8) with 8 Gigs @1020(5:6 ratio) on the ASUS Rampage Formula. Most X38/X48 or P45 chipsets are good overclockers with 8 Gig. Most motherboards require tRFC of 54 or higher with 8 Gig over DDR2-800. As Nukemaster said you will have to up your Northbridge voltage with 8 Gig.

If you are getting DDR2 2Gig sticks and want to overclock I would get DDR2-1000 or higher. With most new Intel CUPs you can get over 400FBS. With DDR2-1000 you will not run into a wall with your memory before most Quads. The 45NM duals will do over 500 FBS with good Air cooling.

When its cooler I run at 3.6 (450X8) with RAM at 900 (1:1)

The P45 Chipset will support upto 16 Gigs of DDR2, But 4 Gig sticks cost alot, The G.Skill 2X4Gig sticks cost $514.99 at Newegg.

1Haplo

I agree. The issue is most likely adding increased voltage to your RAM.

Ohhh right. P35 DS3R needed an extra 0.1 for 4 sticks too. almost forgot that.

I have PDC24G6400LLK all running with added voltage to there specs of 2.2v. I have tried increasing the NB volt on my Gigabyte P35C-DS3R. and using a Silverstone Zues 650W. I can get to 3.4 but after 1 hr of hard rendering/gaming it'll crash.

From the reply's it doesn't look like I will ever be able to really OC high when using 8GB. I havn't found a way on this MOB to run the RAM unlinked but maybe that would help. (I'm running Zalman 9700 in a CM 690 with 4 120mm fans.)

My only option looks to be either staying the the Q6600 or going for something a little bigger like a Q9550 and try to OC a little with it I guess?

I want to stay away from FB-Dimms and all 4GB sticks until I see them compatible with almost all MOB

What are you doing as far as FSB/Multiplier?? Have you tried using a slightly lowered CPU multi and higher FSB??


Things you can do include:

Manually set timings, and ensure the command rate is set to 2T.
Manually set your RAM voltage to (near)Max
***Ensure tRFC is set to 54 or greater***
Bump the voltage to your FSB a notch or two - A little can go a long way.

Usually, that's enough, but you can also drop to a lower memory speed (from 1066 to 800, for example), and that can help ease stress on your mobo.




Q6600 SLACR @ 3.2Ghz (8 multi, 400 FSB)
DFI LP UT P35 T2R LGA 775 Mobo
8GB OCZ Reaper DDR2 800 C44GK 4-4-4-12 2T

Clock Ration 9
CPU Host Clock 400
PCI E = 100
CIA2 Disabled
Performance Enhance = Standard
System Memory Multiplier (SPD) = 2.0
Timing 5-5-5-15

DDR2 Volt = +0.4v = 2.2v which is spec form my Patriot LLK ram
PCI-E = Normal
FSB Volt = +0.2
MCH Volt = +0.2
CPU Volt = 1.38125V

Temp from BIOS no load:
System temp = 40
CPU Temp 45