For gaming raw clock speed, for overall system responsiveness I think you would benefit from more cores.

For XP games . .raw clock speed, games at the time barely used 2 cores let alone 4 so unless you are doing productivity tasks go for two fast cores.

That E8600 can overclock like a beast, Lumi recently had one clocked out to nearly 7ghz to break records, the quad cores dont clock anywhere near as good.

Shagittarius wrote on 2022-09-10, 15:31:

For gaming raw clock speed, for overall system responsiveness I think you would benefit from more cores.

You would be very hard pressed to notice the responsiveness between an high clocked E8600 and a QX9650, I doubt you would even notice unless you were doing production tasks that were hammering 3 - 4 cores. The fact OP is only suggesting a Q9650 means the E8600 would run circles around it for responsiveness, if it was Vista or Win7 then the Quad would likely fare much better.

Former is pointless, because overclocking is a thing.
Does 4 cores help with XP gaming? Depends on your software setup. In regular cases - no. If "XP gaming" is broaden to early 2010s - yeah, quad core will have clear benefit.

The Serpent Rider wrote on 2022-09-10, 15:36:

Former is pointless, because overclocking is a thing.
Does 4 cores help with XP gaming? Depends on your software setup. In regular cases - no. If "XP gaming" is broaden to early 2010s - yeah, quad core will have clear benefit.

Might be if the Q9650 could overclock .. it cant at least not that well, make it a QX9650 and yes I would happily suggest the Quad for a XP gaming rig.
If OP wants to run Vista or Win7 with SLI then that Q9650 would be beneficial, both of which are designed for Quad core CPUs and can use them far more efficiently than XP can.

make it a QX9650

Also meaningless, unless you're heavily constrained by FSB wall. Both use the same stepping, so you'll have both Q and QX shitty binning, depending on your luck. And you can get a bunch of modded Xeons for a price of one QX CPU and bin them.

The Serpent Rider wrote on 2022-09-10, 15:36:

Does 4 cores help with XP gaming? Depends on your software setup. In regular cases - no. If "XP gaming" is broaden to early 2010s - yeah, quad core will have clear benefit.

My XP gaming is centered on late 90s to mid 2000's. Battlefield 2 and F.E.A.R. are about the most recent games I run on that rig.

For anything later, I have a more modern Windows 10 rig.

OC your 8400. Done.

TrashPanda wrote on 2022-09-10, 15:32:

That E8600 can overclock like a beast, Lumi recently had one clocked out to nearly 7ghz to break records, the quad cores dont clock anywhere near as good.

That's good to know. I might try pushing it to 3.5 or 4 GHz. I am using air cooling though and do want to balance noise/temps versus performance.

Agree that for games a fast Core2 Duo is good in XP. If you also do video editing/encoding then the Q9650 would be a better cpu (it cut my editing/encoding time in half versus 8500 Duo) but no improvement in games.

The Serpent Rider wrote on 2022-09-10, 16:04:

OC your 8400. Done.

Install and OC the 8600? 😉

Horun wrote on 2022-09-10, 16:30:

Agree that for games a fast Core2 Duo is good in XP. If you also do video editing/encoding then the Q9650 would be a better cpu (it cut my editing/encoding time in half versus 8500 Duo) but no improvement in games.

Nope, this is strictly for gaming. I am running 32-bit XP, so I have limited RAM for anything productivity related.

I have a dedicated machine for productivity (music/video production) with lots of RAM.

The Q9650 may not overclock "well" but it overclocks fine for me. Limit for me is this motherboard and likely the 16gb of ram I'm running, but since I only use this for compatibility testing I usually leave it at default so it'll last longer. It's stable at overlock though, I leave it benchmarking for 24hrs straight without issue.
DosFreak All System Specs 10-25-2022
Mainly use this for 2K-11 testing. Haven't gotten around to setting up DOS, 9x and NT4 images yet.

+/- 4 Ghz is what you can get on both Q and QX stable, although it will consume power like a hog. Both can and should achieve it on 9x multiplier with 450 Mhz FSB (QX unlocked multiplier is hardly useful). But you don't need it for F.E.A.R., that's for sure. 4.5 Ghz Wolfdale is more preferable.

The Serpent Rider wrote on 2022-09-10, 15:47:

make it a QX9650

Also meaningless, unless you're heavily constrained by FSB wall. Both use the same stepping, so you'll have both Q and QX shitty binning, depending on your luck. And you can get a bunch of modded Xeons for a price of one QX CPU and bin them.

My QX9650 only cost £20 (it's still in my massive pile of hardware to be tested). Love to see the bunch of Xeon with similar specs at that price 😀

Very few early games made effective use of multi-threading. That's because it is actually quite hard to synchronize threads to produce a matching state 60+ times a second. And doing so can actually slow things down. This changed in the 2010s where games did start to effectively make use of multiple cores, however a lot of that was for asynchronous stuff like decompressing textures for upcoming areas or AI (which can be easily decoupled from the main loop).

For a retro gaming rig, I would just stick with a E8500 or even a single-core s775 P4 to avoid potential issues with games not written for multicore CPUs.

I use Windows XP as my main driver on a daily basis.

I recently upgraded from an i3-7100 (dual core), to an i3-9100T (quad core), and the difference in Serpent Browser is significant.

For gaming, dual core is enough. For web browsing, I highly recommend a quad core.

FWIW: I still occasionally play BF42, BF Vietnam, BF2, Halo, Tiberian Sun, Call of Duty World at War, etc on that same system with XP (sp3 32bit) and Q9650. Am using a era equal vid card Geforce-8800GT and it all works just fine.
added: am still using driver 6.14.11.7516 from May 2008 for vid driver, works fine under DX9c

Prob will get best gaming performance from a overclocked dual core. But not by much 🤣 But you may be able to overclock the quad also.

I say go quad if the os supports it.

Games of that era like others have said barely were coded for two threads but even single thread games can be helped with two cores on a multi core os because other processes can run on spare cores.

All in all you won’t notice much difference I suspect, between two and four cores with xp and xp era games. That is. (Clocks being equal)

But quad is cooler. So stick the quad in and overclock it.