What happens if I stick an 800Mhz FSB CPU into a 1066FSB socket?

Through an unusual circumstance my Gateway P-7805U laptop is going to be without its P8400 processor while I wait for an upgrade. (Guy at work wanted to buy my processor, I wanted to upgrade and I can't afford it just yet.)

I have another laptop here with a fried motherboard. It has a T8300 2.4Ghz 3mb cache processor. They are both the same socket I believe. The biggest differences I can see is that the T8300 runs at 35W instead of 25W and it also is only 800MHz FSB and the P8400 is 1066MHz FSB.

Can I stick the T8300 in the Gateway for a month or so and safely use it? I have the OEM 1066MHz DDR3 4GB RAM installed that shipped with it. I really don't know what will happen if I install the T8300 and wanted to ask first.

I honestly won't cry too much if the T8300 gets damaged in the process but I don't want to hurt my laptop.

What do you think? Horrible idea? I just hate being without it.

 

It should work fine. They use the same socket. Problems only arise when you try to install a 1066Mhz CPU on a chipset that won't support it.

 

ahah balane, are you planning to buy a X9100 ?

 

Good glad to hear it will work. Will it be so slow as to be unusable and a waste of time? (Windows 7 Home Premium 64 bit.)

I wish I could afford a CPU like that but I'm just going to grab a T9800 off of ebay or similar.

 

damn go for X9100 / X9000 ;x
now we can overclock extreme CPU

 

Just had a thought, will I have to re-authenticate Windows 7 one extra time doing this? I may just wait if Microsoft is going to make me jump through hoops verifying my software for two processor upgrades.

 

It's not from a lack of desire, believe me, just a lack of enough extra money to buy one.

 

I don't know if Gateway does things differently, but I've changed processors twice (P7350 to X9100 to T9900) and it was simply plug and play.

 

OK, I just tossed it in and checked a few things out.

1st. No authentication for Windows 7 was required. Good.
2nd. RAM, obviously, is running at 800MHz on the temporary processor.

So, clock speed on CPU is up a little bit but FSB has taken a pretty solid hit. Things should be slower right?

But, this is weird to me,

Both CPU & RAM in W.E.I. went from 5.9 to 6.0, Not a big deal.

And, 3DMark06 went from 9700 to 10,150 Now this is a pretty good sized leap.

Ran FRAPs and jumped into a few games for a second or two just to see. Bioshock and Fallout 3. Both had a small gain in FPS

Go figure. Anyway, happy it's running, and running well, on the temporary processor and I won't be without my laptop.

Thanks for the help.

 

The clockspeed between the T8300 and P8400 is slightly different - the P8400 being 2.26Ghz and the T8300 being 2.4Ghz. That should explain the difference.

 

*if* the system bios/chipset are implemented properly, the machine should adjust downward to accommodate the speed of the slowest component.

 

There's no problem using a slower CPU in a faster chipset. The problems occur when you try to go the other way around, i.e. a 1066MHz CPU on an 800MHz chipset.

 

FSB is almost irrelevant performance-wise (unless you are talking about overclocking, in which case increasing FSB also increases clockspeed). Higher clockspeed with lower FSB will always be faster than higher FSB with lower clockspeed, because the RAM speed is never a bottleneck.

 

Passmark rankings are close but the P8400 does edge out the T8300 1540 to 1509.

What I don't understand, and maybe it's just the fact that Windows Experience Index means nothing, is how do my RAM ranking go from 5.9 to 6.0 by dropping the FSB from 1066 to 800? That doesn't make any sense to me.

 

Also the memory running at the lower clock will then also default by the SPD to a lower CAS and other better timings too.

 

I suspect it may be something to do with latency timings.

And the T8300 SHOULD be faster. They have both the same amount of cache, and the T8300 runs at a slightly higher frequency.

 

but P8400 is cooler and slightly newer architecture... i guess..

 

The P8400 is 25w vs 35w for the T8300 so I did get a mild gain in CPU temps but neither gets very warm so it's all good there. I'm actually pretty happy with this "downgrade" and makes the wait for a new CPU much more bearable. Not to mention my friend backed out on the purchase of the P8400 so the wait will now be even longer. :-(