I just built a computer with a A7V8X-X and XP2500 Barton 333fsb. I have one stick of 256 ddr266(PC2100) and one stick of 256 ddr333, both run at 266. The XP2500 runs at 1.83Mhz, but the bios says it running at 1.4Mhz. When I change it to 1.83 a red caution sign tells me that you need ddr333. So do i need to have both sticks of ddr333 ram or does the bios need to be updated to run it at 1.83mhz with ddr266(PC2100) ram.

it's best to match memory and fsb speeds
i have the asus A7N8X with the 2500+ with 2 sticks of pc2700...dump the pc2100 and get another stick of pc2700, so that way fsb and memory is at 333 mhz

Yes, but can I run the XP2500 at 1.8Mhz with pc2100 ram.

Another question, can I run 1.8 ghz at 266fsb, or does it hafta be at 333 fsb.

hey juice, If you have 2 sticks of different speeds ram remove the lesser speed stick and run it at 166 x 11=1826 MHz.when you have enough money buy another stick of (pc2700)preferebly the same brand you already have and your good to go.

It's probably recomended in your mobo manual to run cpu and memory insync.for stability,and as tbird4point6lx97 suggested.

regardless of the error message, try manually setting the memory to different speeds. That pc2100 might run at pc2700 speed or close to it.

If you are going to buy more/new ram. You might as well buy PC3200 or PC3400 and overclock up to a 3200+ by upping the FSB to 200mhz. I have this same board(deluxe model) and chip and with stock cooling 3200+ speeds are very easy to hit without even touching the voltage. If you get better aftermarget cooling and play with the voltage a bit without much special you can hit 2.2ghz - 2.4ghz range. I've been running just over 2.3ghz without any problems. (Temp runs around 42-50 C (HS+Fan Only)

For one thing, they don't make an A7V8X-X Deluxe. He has an A7V8X Deluxe (without the -X) which is NOT the same board.

I would sell both sticks and buy one stick of the fastest Corsair XMS you can afford (not TWINX, just XMS) if you plan on running at faster than 166X2 FSB. Your chipset does not support 400MHz (200MHzX2) regardless of what the bios may offer you in terms of frequency options, so don't try that on your inexpensive board. Even the rev 1x A7N8X nForce boards need a vmod in order to run 200MHzX2 plus with any kind of stability, and that board is much more robust than your's.

Bump your FSB little by little and test your board during 3D gaming or use prime95 to insure you have not gone too far. Leave your multiplier alone.

Your CPU is being held back buy your budget motherboard. With your board I would shoot for no more than 370MHz on your FSB and RAM. Whatever you run make sure your RAM and FSB are 1:1 or SYNC!

If you don't understand everything I just said do not do anything until you do!

Good luck!