A question on FSB, RAM & CPU clock speeds

[DemonSlayer]

I'm just getting into the hardware aspect on computers. I've spent the last few hours reading up on clock speeds, cycles, RAM configurations, FSB and other settings. Must say the information is overwhelming for a newbie, I'm finding it difficult to grasp the meanings.

I have an older computer running on a AMD Athlon XP 2100+ processor. This processor has an FSB speed of 133MHz, but delivers an actual FSB speed of 266Mhz due to its "double pump" feature. I recently bought a 1GB DDR400 PC3200 RAM module. The motherboard has two memory slots. It can support 2 RAM modules @ PC2700(DDR333) or PC2100(DDR266), but only 1 slot can be used if I am inserting a PC3200 DDR400 module.

The jumper setting for the cpu FSB frequency on the motherboard is set to 266Mhz. On the BIOS, the CPU host frequency is set to "auto" and it detects a frequency of 133Mhz.

The DRAM frequency was previously set to "auto" but I changed it to "200MHz [DDR400]" because I thought that gives me fastest speed out of the RAM module.

The DRAM CAS Latency is also set on "auto" on the BIOS. I can choose from 3T, 2.5T, 2T and Auto.

A couple of questions:

1)Shall I set the jumper setting manually on the motherboard to 133Mhz, or leave it as it is currently set to 266Mhz. I thought it might be better to change it to 133Mhz as the processor runs at 133Mhz (but supposedly delivers actual speed of 266Mhz).

2)Is it best to leave the DRAM frequency to 200Mhz - DDR400 or shall I choose a lower setting, or leave it on auto. Is the RAM actually working to its full potential or are there any tweaks I can do to make it run faster.

3)As the CPU has a FSB speed of 133Mhz (266Mhz effective), does this mean that the RAM module can only run at 133Mhz, or can it run to 266Mhz (as that is the effective speed of FSB on this CPU).

4)Can I buy an another RAM module with the same specs as the current one, and then change the DRAM frequency to either DDR333 or DDR266 for both slots so that the motherboard can use them both?

Any help is greatly appreciated, thank you.

[Mickey Padge]

Leave your FSB on 133/266 and run the RAM at 133/266 as well. You can use both sticks without any problems. RAM can always run it's rated speeds or lower, so DDR400 can run DDR333 and DDR 266 etc..... I usually don't touch the mobo jumpers, but it depends on the board you have, if you can change the same setting in the BIOS anyway, leave the jumper as is......

There is no point running the RAM faster than the CPU/Motherboard FSB, as there is no "real world" performance gain to be had from doing so. It is pretty much always best to run the CPU and RAM in synch, EG: 1:1 ratio (133/266 for both CPU and RAM)

What you could do if you have good cooling, is try raising the FSB from 133, to 140-ish. That would increase your RAM and CPU speed very slightly and increase performance. You would probably have to raise the CPU vcore voltage a little bit and memory too, possibly the northbridge/southbridge voltage.......

Keep raising the FSB and see where you get, but only by small increases, and always monitoring temps and running stress test within windows to see if everything is stable (google "orthos")

Otherwise you could lower the CPU multipyler, and raise the FSB beyond 133. For example 133x13=1733, or 166x10.5=1740, or 200x8.5=1700....

The last option there would give you the best performance, as you are running the CPU and RAM at 200/400, while keeping the CPU within its rated speed (Your CPU is rated for 1733mhz)

The main thing to remember is TEMPS and voltages, do not push too hard too soon and monitor things closely, it also depends on your motherboards BIOS settings and options, you may be limited by what you can change if it was an "off the shelf" PC. Also the motherboard may not be capable of running 200/400 1:1 synch with RAM/CPU.....

Cheers!

[DemonSlayer]

Woah!

Thanks M, your answer is much appreciated. I thought this thread wasn't gonna get an answer I'll need some time to digest this info. Cheers bro.

[Mickey Padge]

Woah!

Thanks M, your answer is much appreciated. I thought this thread wasn't gonna get an answer I'll need some time to digest this info. Cheers bro.

No problem, happy to help (I hope!)

I have built lots of PC's way back from the old intel PIII days, and overclocked them too! I have a nice water cooled rig right now, running at 450x9 (quad pumped 1800) 1:1 RAM synched, so that gives a 4050mhz dual core CPU....

It is all about fsb, dividers and multiplyers. With voltage tweaks to keep thing stable, but not too much voltage increasing or things can get hot! That is why peeps invest in crazy large heatsinks and/or watercooling.....

Have a peak over here: http://forums.pcper.com/ I used to be active there a long while ago, but no longer. I am sure you could search up a thread or two that could help you out....

Cheers!