If motherboard doesn't support a CPU made on the same socket (but you still install it), there can happend two things :
1) PC won't POST with "no CPU" beep code.
2) PC will start with "CPU not recognized" error, with smaller frequncy/not working functions.
In Your case it's 100% first option.
Fans will spin at 100% all the time (probably), with error code "CPU not detected".
No support = VRM isn't made to supply voltage for newer CPU's - it can't be "fixed".

Buy a Pentium D 950/945/940 if Pentium 4 is too slow.

Replacing a socket 775 P4 with a Pentium Dual Core normally works without problems. The BIOS does not need to know the CPU. I had a system running with a 2007 BIOS that detected a Celeron Dual Core as a Core2Duo but still worked flawlessly. Only after a BIOS update much later it was correctly detected.

What will not happen if the CPU is not known by the BIOS: microcode update. Not a big deal if you are running Windows, as Windows does that anyway.

derSammler wrote:

Replacing a socket 775 P4 with a Pentium Dual Core normally works without problems. The BIOS does not need to know the CPU. I had a system running with a 2007 BIOS that detected a Celeron Dual Core as a Core2Duo but still worked flawlessly. Only after a BIOS update much later it was correctly detected.

What will not happen if the CPU is not known by the BIOS: microcode update. Not a big deal if you are running Windows, as Windows does that anyway.

Conroe-based CPUs are the Coffee Lakes of 2006.
Just because you have enough pins on your old motherboard (made 2004-2005), doesn't mean you will be able to run it.

P5VD1-X doesn't support ANY Core 2 Duo/Pentium Dual-Core CPUs, only Pentium 4s/Pentium Ds are supported at the high end of CPU options (and Dual Cores are 95W TDP max.).
CPU Support list : LINK
That's why I HIGHLY doubt it will even post.

Read my post again. Only because a CPU did not exist when a BIOS was made does not mean that it will not work. As long as the voltages are supported, chances are high that it will work, even if the BIOS will detect the CPU wrongly.

Apart from that, replacing a P4 by a Pentium Dual Core was probably the most common task people did back then. And nothing bad will happen when trying anyway.

A Pentium D 965 or so would make for a cheap and effective upgrade. Still crappier than the e2140, but would make for a vast improvement over the old 631.

Yeah maybe getting the Pentium D is a better option, but not to me. I don't want to spend money if doesn't need

I recently came to the same question with my ThinkCentre M52 from 2005. The question was which processor to choose to substitute for the P4 631, which, although fast, is only a single core. The upgrade to the Pentium D 940 (3.2GHz DualCore) was well worth it, as for even being able to browse webpages with nowadays number of flash elements on them fluently a P4 won't cut it anymore.

I spent 15 EUR for a P D 940 on ebay, well worth it.

agent_x007 is on the money here I think, when it comes to conroes, this motherboard can't even.

derSammler wrote:

As long as the voltages are supported.

Exactly! And they are not so it won't even post. End of story 😀

Indeed, this motherboard (Asus P5VD1-X) - like one of mine - seems to support CeleronD, P4, P4E up to Pentium D (Presler series).

Your maximum upgrade possibility therefore would be a Pentium D 960, which get rare, but there are a lot of 950s and 940 still available. Beware of the steppings though, it might be that lower stepping versions of said CPUs might be necessary. But from this list, they all seem supported:

Compatible CPU list ---> Asus P5VD1-X ---> http://www.cpu-upgrade.com/mb-ASUS/P5VD1-X.html

You could try editing the bios and add in the 800mhz C2D/Pentium Dual Core and see if it works

Yah, I had a quick cast around for him to see if there were any similar boards (same chipset etc) with a conroe bios, but didn't turn anything up. I mean if it supported as much as a celeron 420, I'd say give it a go.

I have that P5VD1-X, great, dual AGP and PCI-E motherboard! It has 4 slot DDR400 memory, its only insufficiency is, it doesn't support Conroe and Kentsfield CPU's. Is there any solution for that, like modded BIOS?