Why would you not run DOS directly on the i7 (baremetal)? It presumably still has a CSM running option in its UEFI which should allow you to boot a DOS FAT16 or FAT32 .

That’s by far the simplest option and something I hadn’t even considered.

Thanks

BX300A wrote on 2021-04-30, 23:44:

That’s by far the simplest option and something I hadn’t even considered.

Thanks

Happy to help. I hope it works well.

Let us know how it works out, especially if you run some comparison between old and new hardware .

I’ll definitely provide some numbers when I’ve crunched some images. I started wondering about the difference and came up with these rough estimates. I’ll be interested to see how far off the mark I am when I get some real results!

(Below assumes single core processing and 3770K clocked at 3.9GHz)

3900MHz vs 75MHz = 52x faster clock

Assuming an additional 4 x performance boost from CPU architecture improvements = total estimate of 208x faster.

Therefore rendering a frame which takes 1 hour or 3,600 seconds on P75 = 17.31secs on 3770K

To render a one minute animation @ 60fps = 3600 frames. 3770K @ 17.31secs/frame would take 62,316 secs/17hr18m36s.

The Pentium 75 would take 12,960,000 seconds or 150 days. Ouch.

I bet the cache is gonna make that estimate a bit low relative to the actual difference. 32K instruction L1 cache, 32K data L1 cache, 256KB L2 cache *per core*, 8MB of L3 cache, etc are gonna make a huge difference.

Depending, your CPU might have more L3 cache than your program would have used RAM on the Pentium 75, but I don't know how 'real work' workloads work spec-wise on old hardware.

That's supposing you don't hit some other bottleneck though, whether hardware (video?) or software.

Freedos is happy to boot from a USB thumb driver . The memory managers it includes will probably be less fussy with your setup too.

It is tough to say how much faster the i7 will be because of all the weirdness in DOS. It definitely has the potential to be really gd fast.

Error 0x7CF wrote on 2021-05-01, 03:00:

That's supposing you don't hit some other bottleneck though, whether hardware (video?) or software.

Yeah I hope it can stretch its legs unhindered by something artificial like that.

mothergoose729 wrote on 2021-05-01, 03:40:

Freedos is happy to boot from a USB thumb driver . The memory managers it includes will probably be less fussy with your setup too.

I’ll try Freedos too, thanks

Error 0x7CF wrote on 2021-05-01, 03:00:

I bet the cache is gonna make that estimate a bit low relative to the actual difference. 32K instruction L1 cache, 32K data L1 cache, 256KB L2 cache *per core*, 8MB of L3 cache, etc are gonna make a huge difference.

Depending, your CPU might have more L3 cache than your program would have used RAM on the Pentium 75, but I don't know how 'real work' workloads work spec-wise on old hardware.

That's supposing you don't hit some other bottleneck though, whether hardware (video?) or software.

Plus the increased length of the execution pipeline, substantial improvements to speculative execution/out-of-order execution (which was introduced on the Pentium Pro but has been improved massively since then), improved branch prediction, increased number of floating point units, etc, etc. I suspect the actual improvements will be several times greater than the clock-speed differences alone would indicate.

Not to mention memory bandwidth.

Video and disk are unlikely to have any meaningful input into the equation - as far as I can tell it's almost all FPU/CPU bound on the DOS version of the application.