I have an Asus a7v8x-x Mother Board with an AMD 2600+XP cpuand I have installed PC2100 256 X2 DDR ram.
The present setting are 12.5 Multiplier and 166/33 for the FSB.
Could you tell me if these are the optimal setting I can have with the present set up and also how I can overclock-and to what extent and yet not damage the Comp
Thanks
Vijay![]()


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Well first be careful as your RAM is only rated for 266mhz (PC2100) not the 333mhz (PC2700) you're currently running it at. Be sure it is stable, you can higher the RAM timings if it isn't. You have a KT400 mobo which a very decent performer, but like most non-nF2 you are almost certainly limited to 12.5x max multiplier. That leaves the FSB, KT400 were designed for 333FSB operation and use an automatic 1/5 divider to make the PCI/AGP/IDE run at the normal speed. You will likely find the BIOS allows you to go to 400FSB BUT that is NOT likely to work unless you magically have a 1/6 divider (as found on the KT600) needed for 400FSB. So you should find 360FSB (2x180 due to DDR FSB) the maximum as 36mhz is in spec for the PCI but some AGP or IDE devices may not like, even some PCI devices may not like 36mhz. As usual just go up in small steps testing thoroughly for stability at each setting. When you find your limits you may need to raise the CPU voltage (TbredB 1.70-1.75v absolute max IMHO) if you are 100% certain cooling is not the thign holding you back. You could find your cooling limiting but PC2100 is almost certainly the most liekly hinderance ... anyway XP2600+ is hardly bad eh?
When running at a FSB speed you should almost always run the RAM in sync (same speed), usually there's only an option to run the RAM faster NOT slower and the perf hit is usually large for slower ... and faster has minimal gains if any. So...
KT400 are not designed for 400FSB, just 333FSB max but you can o/c, 360FSB is the safest max speed. You should find PC2100 can actually run faster than 266mhz esp if you use slower (higher) RAM timings. Same goes for PC2700 going higher than 333mhz and PC3200 higher than 400mhz, since you're o/c'ing it there are no guarantees and you MUST ensure you are 100% stable if you run it faster than it's rated for. Exactly how fast a given spec RAM can run varies, buying a good brand like Crucial or TwinMOS is well worth it though. So I would suggest buying PC3200 as that is guaranteed up to 400mhz and although KT400 won't hit that reliably it does mean it won't limit your FSB o/c to around 360mhz.
The problem is all that's often quoted about latency or RAM timings is the CL number, it's the most important but less than 1/5th of the story. If you line the timings all up you can state a more complete picture. You should get quoted CL2.0 as being 2-2-2-5 (but could also be 2-3-3-7) and CL2.5 as being 2.5-3-3-7. The 1st number is Cas Latency, 2nd RAS Precharge, 3rd RAS-CAS, 4th Act Precharge (IIRC). BIOS' may use diff notations but that's basicly the principle and lower is always faster as it means less waiting. Other things to look out for are Command: T1 (faster) or T2 (normal) and Bank Mode: off, 2 (fast) or 4 (faster). Anything to do with Memory holes, caches (not L1 or L2), shadowing and the like should be disabled. AGP Aperture is best at 256MB but there isn't (technically) really a perf hit in going lower, it's only assigned if the system has it free and your gfx card's own RAM 'runs out'.
These figures are based around KT333 type era but should still be accurate, if anything it's lower now as most of what Dual CHannel does is reduce latency esp on SktA. Anyway at the same clockspeed 2-2-2-5 is rougly 1.5% faster in Sandra's RAM Benchmark than 2.5-3-3-7. It does depend on what you do with the RAM as to the exact perf diff. Sysmark2000 shows a 4% improvement. Quake3 & 3Dmark2001 show 3% improvement. 2-3-3-7 gives pretty much the same perf as running 2.5-2-2-5.
So bottom line slower RAM timings relate to the higher numbers (more waiting) which you can find in your BIOS under 'Cas Latency', 'RAS-to-CAS' etc. It can be helpful for o/c'ing your RAM (and hence CPU, FSB etc) to use higher numbers and disable things like Bank=4 as although they increase perf a tiny amount they may hold back your system's o/c which should hold bigger gains anyway. The other popular way to make your RAM run at a higher mhz is to overvolt. Overvolting makes the internal signals stronger but seriously stresses your RAM a lot more and will produce a lot more heat too.
