Which CPU to use?

Hi, I have an ASUS P5N-D LGA 775 NVIDIA nForce 750i SLI ATX Intel Motherboard and the BIOS needs updating. I was thinking of just buying a cheap cpu and updating it, then swapping out the cheap for my newer CPU. I have a list of CPUs that i was looking into these three:
Intel Pentium 4 2.8 GHz 2.8ghz CPU Processor SL8HX 775
2.8GHz Intel Pentium 4 Hyper-threading CPU SL8PP 521
Intel Pentium 4 HT 2.8GHz 520J CPU 1MB/800 775 SL7PR

I was wondering which one would be the safest to go with. Thanks

Ok just bumping it and putting in some links...
My Mobo:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813131232R
Was wondering where i could find out exactly which CPUs are compatible with my bios version of my Mobo. I went to the vendor site,my mobo says v1.02 on the bottom of it, and at their site i don't see any of their listings of compatible cpus for this version.

what cpu are you trying to put on the board?

I think you perhaps you would benefit from some in-depth readingof the subject. If the CPU will work on your motherboard, from the ASUS specs, then you just use the ASUS BIOS. Why you think that using a cheap CPU then upgrading would benefit you or your computer, is beyond me.
You will likely create one on which nothing will work.

According to the Newegg link, it looks like any intel CPU, Core 2 Duo or Quad, with a FSB of 1333 or less should work.

"I was thinking of just buying a cheap cpu and updating it, then swapping out the cheap for my newer CPU. I have a list of CPUs that i was looking into these three..."

Hard for me to figger why you would want to do this. Do you think the motherboard cares?

@Kcircyd, he is trying to avoid a situation where a new CPU is not recognized by the motherboard without a BIOS update. So he will use an inexpensive P4 CPU to update the BIOS to the latest version, then pop the new CPU he has bought for the board in.

@treetops, it's a good idea, but only if the current CPU you have installed is not working (i.e. it has gone bad or is not being recognized by the BIOS) AND the P4 CPU you will buy is relatively cheap. Look here for the CPU Support list for your board. There is only one revision of the board according to the ASUS website, so this should apply to any P5N-D mobo.

Ummm treetops, I have a P4 2.93 GHz Prescott that I'm not using (not really intending to use either). Was using it for 4 years before I built my new rig less than 2 months back. I could send it to you for free depending on how expensive it would be for me or whether it would even be feasible.

Ok, thank you very much Rage. Yes, i'm updating my bios cause my new cpu won't work with this version, and my old CPU is not the correct socket type. Only one more Question: What's the default bios version on my MOBO? (i can't start up or anything to check it) My mobo says v1.02g on it, if that helps. This for my bro, thanks for the offer rit, but he will be getting a 15-25$ cpu off ebay. And india is pretty far away.

you will need to get the Pentium 4 cpu first to be able to check your bios version. It should come up on the bios splash screen.

Once you get the system up and running, just download the latest bios for it from the asus website. The latest bios should be newer then what your board currently has.

Yep that's the plan, i just don't know what the default bios is... v107?

You can use the Mainboard tab in CPU-Z to check your BIOS version.

have you tried your new cpu in the board? What cpu is it?

Yeah i have, It's a Core 2 Quad 8400 2.66 LGA775. At first i thought i got a faulty MOBO but i asked around on these forums and i've been told i need to update my bios.

Well, updating the bios is a pretty risky buisness. If you do something even slightly wrong, you could damage your motherboard.

You could always sell your current cpu and buy an Intel Core 2 Duo E8400 3Ghz. That is an extremely fast CPU and should work perfectly with your board. It also overclocks very high (my friend reached 4.6Ghz on air with his). He was using the thermalright ultra 120 cooler with a high performance fan though.

Oh, and the v1.02 at the bottom of your board isnt the bios revision. It is the board revision. The bios currently on your board would more then likely be v107. So if you do decide to go with the E8400, it will work fine.

Wait until the P4 CPU arrives, then use CPU-Z to check the BIOS revision. That'd help you know what BIOS version you have.

Well, its definately v107 or higher as most of the cpu's on the support list (including the celerons) require at least v107.

But still, Do what Rage said and check the bios revision using CPU-Z when the Pentium 4 arrives, That way, you can be 100% sure.

Actually, if the board in question has an "Award-Phoenix" BIOS, you can simply watch the BIOS boot screen and watch the revision number roll by.

Under BIOS revision v.107, Asus lists only 65 nm CPUs as being supported, the "Allendale" 4xxx series being the most prevalent.

http://asus.com/product.aspx?P_ID=yQYfAtkxxZMjR79G&templete=2

IMHO; the Asus web site CPU is listing incomplete and/or not up to date. This because it shows a "Wolfdale" Celerons (E32 &3300(both 45nm)) as being supported w/ BIOS revision v.1101, but makes no mention of the other 45nm process CPUs that would run under the same microcode. I recommend Emailing Asus support and see what, (or if) they have anything to say on the subject.

If money is an issue, my personal choice would be to go ahead and update the BIOS, (assuming it's not v.1101 already), and purchase the Celeron E3200 while I saved my money for the higher end C2D CPU. This particular Celeron would easily outperform any P-4 that you might be able to find.

As has been mentioned, updating a BIOS can be a risky affair, but if you read and reread the instructions very carefully, it is do-able, and judging by the support list of the older v.107, it is necessary.

Ok, Thanks for all the input. I went ahead and bought a 2.8GHz Intel Pentium 4 Hyper-threading CPU SL9CG 521 and put it in my MOBO today to update the bios. It's not giving me a beepcode or posting or anything.... Could i have a bad MOBO? (i've tested all of the other components and they are solid)