Higher FSB means more stress on the Northbridge, may need to increase Northbridge voltage in addition to vcore for stability and provide some passive cooling. ie EVGA mobo comes with a NB fan.
Running high FSB are usually for lower end CPU such as E6300/6400 that has a lower multiplier. For a X6800, it's difficult to reach high FSB without decreasing the multiplier or VERY VERY good cooling like phase change cooling (liquid nitrogen).
Oh and memory performance gain is small compared to CPU gain. Running memory at 800 is not much difference compared to 667, most likely it'll show up in benchmarks (a few fps difference). So I guess if you want bragging rights with having the highest 3DMark Score then go for it.
RATED_FSB| RAW_PTS | IMPROVEMENT
1066 | 204.657 | over previous---| over 1066 1333 | 172.297 | 16%
1466 | 157 | 9% | 23%
1600 | NOPE! FTB | uh?.. it IS quieter.
MSI P6NSLI Platinum/E6400/PDC22G6400LLK (2gb)
Raw_PTS is aggragate '2M' and '4M' times.
All runs at 1:1 fsb/dram ratio; DRAM CL4/1T.
The MSI P6NSLI Platinum supports the 1333FSB natively; the E6400 is a 266.7MHz processor, and the ram is rated CL4/2T @400MHz.
How the h@#! does one align columns in BBC?
Admirable effort but an invalid comparison. The increase in performance is because you're overclocking the CPU along with the FSB. To provide a valid comparison you'd need to increase the FSB and drop the CPU multiplier to keep the same clockspeed. Also, to be fair you should tighten/loosen the RAM timings to suit the FSB speed. For example, it's not fair to run 1600MHz FSB on the same RAM timings as 1066MHz FSB, because you can certainly achieve better timings at 1066.
To answer the original question, generally you should always try to run memory in sync (1:1) with the FSB. So you should run DDR2-800 at full 800MHz with 1600FSB and drop the CPU multiplier if you need to, or keep the CPU multiplier at max and raise your FSB to achieve your desired overclock. Run the RAM in sync with your FSB and if it's slower than the rated speed (eg, DDR2-800 running at 667MHz) tighten the timings.
that is what I "want" to do but I cannot seem to boot with FSB much over 350?? I have a post going on this matter in another section but want to find out if there will even be any difference. If not them im wasting my time.
But i felt that running my DS3 rev 3.3 at 400fsb give or take. My E4300 at 7x and thus run 1:1 memory would take the best advantage of my hardware. Which if anyone is interested.
Maybe you need more chipset or memory voltage (most DDR2-800 memory modules need 2.0 or 2.1v to run at rated specifications) but seeing as that's not the main issue here anyway, I'd say it's not a big deal. The performance increase from running 800MHz with a lower multiplier would be minimal. Probably not even noticeable for all intents and purposes, especially if slower RAM speed lets you tighten the timings.
When I was overclocking, I benchmarked various settings including 400MHz FSB with a lowered multiplier, and eventually settled on the full 9x multiplier with underclocked RAM.
A 400MHz FSB is shooting pretty high with an Allendale. That's 100% OC. Have you tried a vcore increase and vmch (northbridge volt) increase? I've noticed that a 400MHz bus will not boot unless I turn up the vcore between 1.35v - 1.40v (+0.10 - +0.15v on the DS3) and a +.1v on mch. Your processor will run 40-45C idle though, on good cooling that is, about 50-55CC on stock.
Like someone mention earlier, lower memory frequency can enable looser timings so you don't have to run the memory at its rated speed.
Ok, this is a little bit of a thread hijack… but it seems to be a similar question.
I am running Socket 754 Athlon 64 3200 venice core. It is on an Epox mobo that does not allow AGP/PCi locking, so upping the FSB is out of the question. The hitch in the system is that I am running it with 2x512 pc2100 ram. So, it is using a divider to run the ram at 133/266 ddr. Obviously the system would be the best with pc3200, as that would run with a 1:1 ratio.
I am happy with the performance, everything runs great. But I am curious it I “loosen” the timings, could I run this ram at a higher speed…i.e. 166 or 200 mhz?
It is corsair value ram, and I think cpu-z said my timings were 2-3-3-6.