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Memory speed/FSB and overclocking for a gaming rig

  • Memory
  • Overclocking
  • Gaming
Last response: in Memory
June 12, 2009 6:26:46 PM


Just a quick question.

I'm getting an Asus P5N-D with an Core 2 Duo E8400 3.0 GHz, 1333 MHz FSB (and i MIGHT go for the Q8400 instead), with 4GB of 800 MHz DDR2.

Other feature sof this rig are:
896MB 275 GTX.
640GB Hard Disk
Antec 900 gaming casing
450W Quiet Dual Rail PSU + 120mm Case Fan

The calculated power requirement of my system comes to 451w. I figured 450w shud do for now. In the future, I may get an 800w supply, an extra 275GTX and another 640GB hard disk for Raid 0.

For now, I want to use this system as is with the 1333 MHz FSB/800MHz RAM, but i may want to overclock it at some point (and overclock the GPU).

From what i've read on these forums it seems my 1333 MHz FSB Vs 800 MHz RAM is fine because, as i understand it, the FSB is quad pumped and the RAM is dual channel. so 1333/2 = 667MHz is my effective (and required) RAM speed. However, if I plan to overclock, I can expect a boost of about (800-667)x4 increase in my CPU clock. i.e. 133 MHz x4. So my 3.0 GHz CPU is effectively overclockable by 533 MHz (approx) to a speed of 3.5 GHz

so my questions/issues are:

1) If my calculations (assumptions are wrong), please do correct me.

2) Is 3.5 GHz a good overclock for my CPU? Should I be aiming higher? (taking note of the case/powersupply/cooling I'm buying).

3) Should I go for the 1066 MHz RAM instead to get a better overclock? It's about £50 more for 4GB, so it's a cost i'd rather avoid if it's not worthwhile. For example, wouldn't going from a 275GTX to a 285 GTX be a bigger performance hike than faster RAM (with the higher overclock)?

For now, i'm going to stick to my build, but please critique and let me know if my cooling system/case are overkill for the system i'm putting together, and whether that cooling system will hold up under the maximum overclock i can manage iwth my E8400 (or Q8400) with 4GB of DDr2 800.

Thank you

More about : memory speed fsb overclocking gaming rig

June 12, 2009 6:29:23 PM

I forgot to mention. My main purpose of the rig is gaming. Especially Real-Time Strategy games like Company of Heroes, Grand Ages: Rome, Men of War, SC2 (when it releases), and also future MMORPGs.

And i'll be using this on a dell monitor at 2048x1152 or 1920x1200 resolutions.
September 15, 2009 3:15:29 AM

Try this power calculator to confirm power supply required.

The Statement:
RAM is dual channel. so 1333/2 = 667MHz, is not correct, it should be

RAM is Double Date Rate so 1333/2 = 667MHZ

If the BIOS has the memory setting set to AUTO, then a FSB:RAM ratio 1:1.2 will be used, and ram should run at 800 MHZ.

If you overclock the CPU FSB to 400 MHZ, then the FSB:RAM ration will be 1:1, one of the easy overclocks to do, and gets you a speed of 3.6 GHZ (400x9).
Note: Additional CPU cooling maybe required.