dual channel question, RAM and cpu

[discodanman45]

Quick question about running dual channel with my mobo. I have a ASUS P4P8X SE mobo and I have a 1.5 GHz P4 400 MHz FSB. Now in the manual it says that if I have a 400 MHz FSB I can only use PC2100 DDR for dual channel. Now I have two sticks of SpecTek PC 2700 and can only run dual ram if I have a 533 FSB processor.

If I attempt to run dual RAM would my mobo run the RAM at 2100 or at 2700. Or would it just be unstable and cause my computer to crash? Plus it is not great RAM, so I am thinking running dual channel may not be the best idea.

Another quick question, can you put a 800 MHz FSB processor into a mobo that supports only 533??????? I can over clock to 800 Mhz, but if I do that I can only use PC3200 RAM. I want to get a better processor, but don't want to get another mobo. I am thinking just to get a 533 CPU FSB at about 2.4-2.6 GHz to upgrade my 1.5 GHz processor.

[Andrew Downie]

First,
The ram should underclock itself to 2100 from 2700 i.e 266mhz from 333mhz.

Secondly, That motherboard you have does is capable of an 800FSB. as it says on the Asus website. So Yes, it should.

Hope this Helped.

AD

[DriftWolf]

Many 800mhz fsb cpus will run at 533mhz. I do not belive that you can overclock a fsb. Could be wrong. Anyway don't worry about that because your mobo will run a 800fsb.

[Cricket]

Originally posted by DriftWolf I do not belive that you can overclock a fsb.

Sure you can...with the right motherboard. Many name brand computers use motherboards that don't allow this, but most aftermarket ones do.

Cricket

[mikezel]

Originally posted by DriftWolf I do not belive that you can overclock a fsb.

as Cricket said, thats actually untrue...with most of today's processors having their multipliers locked, the main method of overclocking has become raising the fsb.
mike

[discodanman45]

Ok, I am a bit confused. My mobo says that it only supports 533 MHz FSB, 800 if overclocked. So if I put a 800 MHz FSB cpu into my computer what will happen?

Also it says that if I overclock to 800 MHz FSB that I can only use 3200 RAM. I have 2700 RAM and don't feel like getting new RAM.

So I would like to get a 800 MHz cpu, but wouldn't mind running it at 533 MHz if I could do that. Because if I have 533 FSB I can use 333 Mhz RAM in dual channel.

I think that you all agreed that my 333 Mhz RAM will run at 266 MHz on my mobo when I use 400 MHz FSB, so this is not a problem. Besides that I am still a little confused. Thanks for the help.

[Cricket]

Originally posted by discodanman45 Ok, I am a bit confused. My mobo says that it only supports 533 MHz FSB, 800 if overclocked. So if I put a 800 MHz FSB cpu into my computer what will happen?

If you run the 800MHz CPU at 533MHz speeds, it will be underclocked. If you take a 2.4GHz 800MHz and put it on your motherboard and run the motherboard FSB at 133MHz, you'll have a 1.5GHz 533MHz processor. If you try to overclock the motherboard to get the 200MHz FSB speed (which is what the 800MHz CPU uses), you might end up with a real unstable system or it might not even boot to Windows (if your motherboard can't lock the AGP and PCI buses).

Originally posted by discodanman45 Also it says that if I overclock to 800 MHz FSB that I can only use 3200 RAM. I have 2700 RAM and don't feel like getting new RAM.

If you run the motherboard FSB to 200MHz, the RAM will be overclocked and if it's not good quality stuff, you'll end up with an unstable system or a system that doesn't boot to Windows...or it may not even boot up at all.

Originally posted by discodanman45 So I would like to get a 800 MHz cpu, but wouldn't mind running it at 533 MHz if I could do that. Because if I have 533 FSB I can use 333 Mhz RAM in dual channel.

That's totally up to you...but it's a big waste to run a 800MHz CPU at 533MHz (you saw how much CPU speed you lost in the above example).

Originally posted by discodanman45 I think that you all agreed that my 333 Mhz RAM will run at 266 MHz on my mobo when I use 400 MHz FSB, so this is not a problem. Besides that I am still a little confused. Thanks for the help.

Underclocking RAM isn't a problem. Underclocking a CPU isn't a problem either. It's when you start to overclock that you can have stability problems. So, if you want to run your PC2700 at PC2100 speeds, that's fine. And if you want to run your 800MHz CPU at 533MHz speeds, that's fine too. Just seems like a real waste to not get the performance those parts are capable of.

If your motherboard allows it, you could run asynchronous...run the CPU at 800MHz (200MHz) and run the RAM at 333MHz (166MHz) and lock the AGP and PCI buses at 66MHz and 33MHz...but you can have stability problems running the system this way.

Cricket