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Best configuration for a Q8400

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  • CPUs
  • Configuration
Last response: in CPUs
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March 21, 2011 3:15:51 PM

A friend has ordered a Q8400 for his rig, and seeks advice as to what is the most optimal configuration for the CPU whilst being configured with a single 2GB 1066MHz DDR3 DIMM (he is also looking to add additional memory ~ perhaps another 2GB DIMM or a 4GB one). I have advised adding another of the same DIMMs as RAM usage isn't necessary above 4GB unless image or video rendering is in order, and due to Column Address Strobe latencies and voltages being different.

The CPU of course has a FSB of 1333 with a multi of 8.

I am not too sure as to what multiplier choices are available, such as including decimals (e.g. 6.5). 6.5 seems to get the CPU at 1083 FSB, this is close to the RAM. As they are of course linked, I cannot seem to find a multiplier that gets them at a 1:1 FSB/DRAM ratio. Although it is a myth as to whether it suffices real-life in-game performance increases, it seems to be proven in some cases and not in others. I was thinking that it seems most advisable when the clock cycles are not parallel, otherwise they will be imminent.

Should it just be left at stock (don't worry about the GPU and bottleneck situations for now, although it is a GTS450 and I have advised 3.1GHz)?

P5G41C-M LX is the motherboard that he has put into use.

I know my stuff, but I cannot seem to find an optimal multi to use with the BC in order to suffice a 1:1 ratio or any optimal configuration for that matter.

More about : configuration q8400

March 21, 2011 11:55:48 PM

Bump
March 22, 2011 12:52:38 AM

If your shooting for a 1:1, I think you misunderstand RAM. DDR2 operates at double the base clock, and a FSB operates at quad.

For example, I have a Q9450. My reference clock of 375. That puts my RAM operating at 750, and my FSB at 1500. In this scenario, they are operating at 1:1.

For your CPU, DDR2 667 would operate at 1:1 for that FSB. What you have done in buying the 1066 RAM is alloed yourself to hit 2132 FSB (or 4.264 GHz) without overclocking the RAM. This does though allow you to run, lets say, 1600 FSB (or 3.2 GHz core) and have your RAM timed at 3-3-3-9 (best case) because of your overhead, and reduce system latency, making the communication between the RAM and CPU more efficient.

The high multi gives you more processing power, where as the lower (X6) would allow you to push your FSB up without overclocking the CPU so much, and increase through put. But that gets into scenario specific benchmarks.

Anyway, hope this helps.
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March 24, 2011 3:18:22 PM

azconnie said:
If your shooting for a 1:1, I think you misunderstand RAM. DDR2 operates at double the base clock, and a FSB operates at quad.

For example, I have a Q9450. My reference clock of 375. That puts my RAM operating at 750, and my FSB at 1500. In this scenario, they are operating at 1:1.

For your CPU, DDR2 667 would operate at 1:1 for that FSB. What you have done in buying the 1066 RAM is alloed yourself to hit 2132 FSB (or 4.264 GHz) without overclocking the RAM. This does though allow you to run, lets say, 1600 FSB (or 3.2 GHz core) and have your RAM timed at 3-3-3-9 (best case) because of your overhead, and reduce system latency, making the communication between the RAM and CPU more efficient.

The high multi gives you more processing power, where as the lower (X6) would allow you to push your FSB up without overclocking the CPU so much, and increase through put. But that gets into scenario specific benchmarks.

Anyway, hope this helps.


I know the BC is half on the CPU, hence "dual-channel".

I mistakingly wrote the speed at half. I'm used to doing those calculations by doubling them up, and then halving them (I personally find it easier with having the same number/only to remember it once (then half it later)).
March 24, 2011 3:24:26 PM

Quote:
the cpu cache takes care of the ram latencys most of the time. ill advise him to get a good cooler. Those E8xx cpus are beasts when it comes to overclocking. 4gb ram will be enough. More is a bonus.
But the higher speed ram will provide more headroom when overclocking it.


It's a Q8xxx CPU. Not an old 45nm dual-core 775 chip.

The cache is only 4MB (half of my 65nm's 8MB [Q6700]). Not an immense amount, but not too low either.

I've advised something like a Cooler Master Hyper series or a low end Noctua cooler... something like a U9B-SE2 beforehand, but he says he'd be fine with the stock cooler. I remember even at stock clocks my Q6700 stuttered when stressed in games intensively (probably over a Q6700s recommeneded 58-62C [before it runs into issues]) with a stock-like heatsink (A Foxconn one to be precise ;P).

Ah, when they were out, those old E8xxx CPUs were literally "beasts" as you said though, especially for single GPU setups. (Of course quad cores and above give a lot more throughput for the GPUs; therefore being favoured by multi-GPU users such as myself).
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