E2140 and P5K-VM no more than 340MHz FSB

I just built a Apevia Qpack-2 uATX based box. I had bought a Asus P5k-VM uATX board (G33) and a E2140 CPU (MO stepping) to go with this setup but couldn't get the CPU above 340Mhz bus. So basically I was stuck at 333Mhz x 8 = 2.66Ghz. I could actually lower the voltage to 1.17v and run orthos CPU stress test at that speed.

I knew from experience that the E2140 should do 3GHz plus. I had just built a friend a new PC based around the Asus P5K (P35 chipset) and a E2140 MO stepping. That CPU ran flawlessly at 400MHz x 8 = 3.2GHz.

So I went over my nephew's house and installed my new E2140 in his Asus P5K Deluxe WIFI (P35 chipset) and we ran 415Mhz x 8 = 3.22 GHz. @ 1.4v Around 425Mhz it was flakey and refused to boot. We used a Zalman 9700 heatsink and upto 1.55v but achieved no stability at 420+ Mhz. We could run 1.35v @ 400Mhz for 3.2GHz with perfect stability. That FSB limit was with all the multiplyers as well.


We traded CPUs and I put his E6300 in the P5K-VM board and ran it at 470Mhz x 7 = 3.33Ghz at 1.4v with a Cooler Master Hyper TX2 (Qpack-2 required cutting of the support and removal of the 3.5" HD tray to use this cooler).

So there is a problem running 800FSB CPUs in the Asus P5K-VM at high bus speeds, simular to what I experienced with the Asus P5B-E (P965 chipset) with a E4300 stopping around 350Mhz.

If you want to run 3Ghz you are probably better off with a CPU with a 9 multiplyer so you can run 333MHz x 9 = 3GHz incase your mb doesn't like 800FSB cpus.

Google e2140 FSB wall and you will have the knowledge you seek.

Are you suggesting that I do a BSEL mod? I already tried that on the E2140. The P5K-VM boots the E2140 @ 2.13GHz native after the BSEL mod but will not allow a setting of the CPU in BIOS to anything. Even if you set the BIOS to Auto if will not boot. Resetting the BIOS will allow the board to Boot and you can hit F2 to load BIOS defaults and continue into WIndows XP and confirm the CPU is running 266MHz x 8 = 2.13GHZ. I don't think Asus boards like BSEL mods.

Please be specific as to explain motherboard behavior with 800MHz FSB CPUs and why some boards that can run 400+ MHz FSB on 1066Mhz CPUs can't do so with 800FSB CPUs. It may have something to do with FSB strap but how can we determine this before purchasing a motherboard?

Jerry

n/m

jerrytbirdsc said:

If you want to run 3Ghz you are probably better off with a CPU with a 9 multiplyer so you can run 333MHz x 9 = 3GHz incase your mb doesn't like 800FSB cpus.

Click to expand...

I've run an E2160 at 3Ghz in a P5K-VM without problems. Considering the E2160 is only $8 more than the E2140, I really didn't see the point of saving myself such a tiny amount of money when I knew the E2160 would be easy to hit 3Ghz... glad I did, because the E2140 sounds like even more trouble than I thought it would be. (If you can trade in the E2140 toward the purchase of an E2160, I would.)

I can't get my mobo to do 400x9. I have to run it at 320x10. It won't even do 340x10. I'm thinking that the vdroop is holding it back and my ram really wants 2.2v.

I put together a E4300 and a Asus P5B (P965) in March and I had simular issues in that you can't boot more than around 370Mhz FSB. It's been my daily computer running at stock voltage at 333Mhz x 9 = 3.0 GHz.

The E2140 only cost $71 shipped so no big deal, it will just go in a P5K (P35 chipset) motherboard and live out it's life at 400MHz x 8.

I just didn't expect a G33 chipset board, that was native 333MHz, would limit the E21XX series to around 350Mhz FSB as my older P5B board. did.

You really have to watch out for the pitfalls, with the Gigabyte uATX boards forcing 3.3x and 4x memory multiplyers on 800 FSB cpus Asus was the only game in town in my mind.

Still happy with the performance and quality of the P5K-VM, maybe some day we will have a perfect uATX board.