Keep in mind, older Pentium 4s are kinda hot and power hungry.
65nm Cedar Mill's (Pentium 4 6x1 series), are the best Pentium 4's (reduced temps and power draw).

Why Single Core ?
Just buy a Core 2 Duo.
OS will only use one core from it - true but, so what ?
It's not like they cost hundreds of dolars and if you ever decide to dual boot with Win XP, it will help A LOT with it's games.

I'm already planning a winxp standalone rig, mainly because of the ram limations between the os's and I don't know how to handle it on one machine, it would also require a motherboard that has one agp and one pcie slot or two pcie slots possibly.

Edit: just bought a celeron 450 for two bucks, I may just buy a few cups since there are all pretty cheap and run my own tests.

agent_x007 wrote:

OS will only use one core from it - true but, so what ?

If this^ is true, and Win98 can be installed on a machine with a multi-core CPU and will "ignore" the extra cores without errors (since the 775i65G R3.0 manual doesn't list a BIOS option to disable extra cores), then yes, you should find a C2D-based CPU. The faster ones will outrun any P4 in single-core performance and will also run cooler.

In the case of the 775i65G R3.0, the fastest would be the Pentium E5800 @ 3.2GHz. (The CPU support list has 1066MHz FSB processors as well but these require an AGP card to be installed + CL2.5 DDR-400 memory; if you have both of these, you could use a Pentium E6800. The list also has a Pentium E5900, but I don't think these are easy to find.)
EDIT: spelling

as far as I know windows 98 simply ignores the other cores and works happily;

the mentioned e5800 is super cheap and should be pretty fast at 3.2GHz,

E5800 is the best CPU you can put onto it. Make sure it's the R3.0 version of the motherboard you have. It has to have a black PCB. It's the best CPU with official 98SE support. Don't go with Q6600, even though it is supported, the 1066 FSB causes severe boot times increase, and lower DDR memory performance.

MrMateczko wrote:

E5800 is the best CPU you can put onto it. Make sure it's the R3.0 version of the motherboard you have. It has to have a black PCB. It's the best CPU with official 98SE support. Don't go with Q6600, even though it is supported, the 1066 FSB causes severe boot times increase, and lower DDR memory performance.

how come an increased fsb rate slows down boot and memory?

yep, the E5800 has a 800mhz fsb ?

E5800 has 800Mhz FSB, so full motherboard performance on it, no hacking. Get it.
Here's full list of CPU supported by 775i65G R3.0:
http://www.asrock.com/mb/Intel/775i65G%20R3.0 … dex.asp?cat=CPU

ASRock's implementation of 1066 FSB support on the 775i65G R3.0 is kinda hacked. They make the DDR run at the slowest 133Mhz, with no option to change that. They do other hacking with other base clocks as well during the boot up, that's why it's taking so long.
It's not worth it, you want the system to boot up fast, not slow.
Bear in mind, I'm telling from what I read from other people on the internet, I do not have this motherboard, nor a 1066 FSB CPU. For more info, try looking up people who has the same motherboard, and a 1066 FSB CPU.

I'm 9 years late to this forum thread, but I have this motherboard. It came to me with a Q6600 and it was ungodly slow at even the most basic things in the OS, so I went and bought a Pentium E5800 as they're still plentiful and reasonably cheap. 98SE seems to work pretty well so far, well at least as well as 9x can - though I may need to limit the RAM to 512MB as I have had a few "out of memory" errors.

i use asrock 775i65g r3.0 all time, i try P4 631 dD0, Celeron 430, 450, C2D X6800, E7500 and E5800 under windows 98se, 98if, ME. E5800 simple the best (tdp, voltage, stable and ect) I use it with Voodoo 5500 and FX5900. dos games us mdk and 200x games us Oni. Allways e5800 don't have any problems.

E5800

The others have clocking problems, so while being faster on paper the motherboard BIOS and chipset implementation make the E5800 the best choice.

Not only that you can pick one up for less than £10

ElectroSoldier wrote on 2026-10-04, 10:51:

E5800

The others have clocking problems, so while being faster on paper the motherboard BIOS and chipset implementation make the E5800 the best choice.

Not only that you can pick one up for less than £10

Clocking problems ?

So the listed X6800 and QX6800 support have issues ?

Im curious how these problems manifest ? is it general instability or just problems running at their rated clock speeds ?

Its native bus speed is quad pumped to 800MHz, while it can run 1066MHz it has to overclock at an asynchronous rate leading to instabilities in 1066 chips.

I found instability is there but intermittent, it might not come up for several boots but then for no real reason games would crash.
It might well have been my RAM but I dont think so. I am using Geil memory which was good at the time.

Some of the later P4 CPUs have a higher clock rate which suits Win98, but the higher IPC of the E5800 and its 3.2Ghz clock make it a better choice.

ElectroSoldier wrote on 2026-10-04, 11:15:

Its native bus speed is quad pumped to 800MHz, while it can run 1066MHz it has to overclock at an asynchronous rate leading to i […]
Show full quote

Its native bus speed is quad pumped to 800MHz, while it can run 1066MHz it has to overclock at an asynchronous rate leading to instabilities in 1066 chips.

I found instability is there but intermittent, it might not come up for several boots but then for no real reason games would crash.
It might well have been my RAM but I dont think so. I am using Geil memory which was good at the time.

Some of the later P4 CPUs have a higher clock rate which suits Win98, but the higher IPC of the E5800 and its 3.2Ghz clock make it a better choice.

This affects the Rev 3 boards ?

Yes.
I thought it wouldnt so I got one off ebay, I had a 2.03 but then paid through the nose for a 3.0 thinking because the support list of the 3.0 was extended it would be better so worth it, but all it really did was remove that anoying 10 second delay to the cold start as the microcode calibrates the low voltage VID required...

Dont get me wrong it a good board, for Win98 its lovely and without a double thee board I spent most time and money on getting working with Win98 properly... even went and made it so I can use a zip drive as a Win98 boot floppy.
Gives you some idea of the weeds i dug though to make it work the way I wanted it to.
And it does, its sweet, a right little darlin!

X800XL with Voodoo2 SLI etc etc.

So I can highly recommend the board for a Win98 project, even the 2.03 boards but you will have to live with the VID delay.

ElectroSoldier wrote on 2026-10-04, 12:07:

Yes. I thought it wouldnt so I got one off ebay, I had a 2.03 but then paid through the nose for a 3.0 thinking because the supp […]
Show full quote

Yes.
I thought it wouldnt so I got one off ebay, I had a 2.03 but then paid through the nose for a 3.0 thinking because the support list of the 3.0 was extended it would be better so worth it, but all it really did was remove that anoying 10 second delay to the cold start as the microcode calibrates the low voltage VID required...

Dont get me wrong it a good board, for Win98 its lovely and without a double thee board I spent most time and money on getting working with Win98 properly... even went and made it so I can use a zip drive as a Win98 boot floppy.
Gives you some idea of the weeds i dug though to make it work the way I wanted it to.
And it does, its sweet, a right little darlin!

X800XL with Voodoo2 SLI etc etc.

So I can highly recommend the board for a Win98 project, even the 2.03 boards but you will have to live with the VID delay.

I have a Rev 3 board and was hoping to throw a X6800 or QX6800 at it but if it has issues then Ill just put a E5800 in it.

I never looked into the quad core CPUs because I was interested in Win98.

ElectroSoldier wrote on 2026-10-04, 12:34:

I never looked into the quad core CPUs because I was interested in Win98.

Yeah I was planning to dual boot it, its a nice enough board to go the extra mile and throw XP on it too.

It is a nice board, and its powerful enough to re live the early WinXP days with.
I did that with the rev 2 board I had until it finally sold on ebay (sold it to offset the cost of the rev 3.0 board)