wrote:BTW, the thing score 49 pts in speedsys - that's as much as a 133MHz 486 - is that normal?
According to this, a Pentium 75 scores 55.91 in speedsys. So extrapolating that to a Pentium 66, 49 seems fine.
UPDATE
After a long period of messing with it on and off, I finally got it to work... it now uses 512kb of L2 cache, and a 16k tag ram chip.
It turns out there were 2 issues:
1. Cache ram was 20ns - not rated for 66MHz operation. I'm guessing someone took the 15ns chips it was supposed to come with and stuck on some 20ns chips off a 486 motherboard.
2. Cache was incorrectly configured - TAG was set to 16kb when it was in fact an 8kb chip.
To get it to work, I replaced the 20ns cache chips with 16 UMC 32k x 8 (512kb in total) and the TAG cache chip with a 32kb chip (set to 16k from jumpers). The machine now works perfectly. It also gets ~ 19.2 FPS in dos quake, witch is surprising consideting my 83MHz POD5V only gets ~ 17.... what a difference double banked cache will make...
The board seems to be a pretty good performer. Pentium60 stuff is always appreciated.
It's a bit odd... I got the 19 FPS in quake using a matrox millenium II 8mb PCI card - with a 2MB Cirrus VLB card it gets ~ 16.4, and with my trusty trident 9440 (VLB, 2MB) it gets 17.2 - my only problem so far is HDD performance... it is SLOW. The drive itself is ok - not a slow drive for the period - and I am using a VLB I/O card - but for some reason HDD performance is pants. Main memory throughput isn't to great either ~ 78mb/s in speedsys - but I haven't started tweaking timings in bios yet.
Right now, it seems PCI performance is excellent, while VLB performance is meh.
wrote:Right now, it seems PCI performance is excellent, while VLB performance is meh.
That is also how I remember Pentiums with VLB buses.
The VLB bus connects directly to the 486 socket. I don't know how it is implemented on a Pentium, but I wouldn't be surprised if they need some kind of bridge chip. Perhaps the performance of the bridge chip explains this.
wrote:wrote:Right now, it seems PCI performance is excellent, while VLB performance is meh.
That is also how I remember Pentiums with VLB buses.
The VLB bus connects directly to the 486 socket. I don't know how it is implemented on a Pentium, but I wouldn't be surprised if they need some kind of bridge chip. Perhaps the performance of the bridge chip explains this.
You right. Traces from the VLB slots seem to lead to a UMC UM82C206F chip - witch is a Integrated Peripheral Controller. Here's a datasheet for it: http://pdf.datasheetcatalog.com/datasheet/UMC/mXyztwsr.pdf - a few traces go directly to one of the OPTi chips.
The wiki page mentions an Opti chip:
https://en.wikipedia.org/wiki/VESA_Local_Bus
Few Pentium motherboards with VLB slots were ever made, and used VLB-to-PCI bridges such as the OPTi 82C822.
And a link to its datasheet: http://bitsavers.informatik.uni-stuttgart.de/ … o_PCI_Apr94.pdf
Interesting. That means most traces go trough one of the middle layers of the board. But some go to the UMC chip - wonder what it does..
wrote:Interesting. That means most traces go trough one of the middle layers of the board. But some go to the UMC chip - wonder what it does..
Judging from the datasheet, the UMC chip mostly supplies legacy PC/AT support, like the DMA controller, PIC, timer and CMOS chip.
Done testing. I put 64Mb of FPM on it - with 512kb of L2 cache it should be able to cache all of it. After tweaking cache and memory timings in bios, dos Quake (1.08) with sound gets ~ 18 - 18.2 FPS with the Trident 9420 vlb, and alltough a low number the game is oddly playable. I've gotten better FPS out of 586 rigs (Cyrix 5x86 @ 120 /w enhancements enabled) but it's not as smooth - quake on a 486 platform is kind of jittery especially with mouselook enabled, even with a POD5V 83 on a fast motherboard - but it feels smoother and more playable on this guy. GL_Quake gets 22.4 FPS with miniGL 1.49 and a voodoo 2 12MB, again, playable - although it seems to stutter a bit more then dos quake. Overall I'm pretty pleased - I think I found my new "retro feel" DOS rig 😀
Final configuration is:
Pentium 60 or 66 (no idea what speed it's intended to be, the writing on the chips was cleaned off) @ 66MHz
64MB FPM 60ns ram (4x16MB)
QDI Legend VIP596P3 with 512KB 15ns L2 cache - made in 1994
Trident 9420DGi 2MB VLB - made in 1994
Creative Sound Blaster 32 (CT3930) - made in 1995
Kentech VLB mutli I/O card (goldstar chipset) - made in 1993
Miditower AT case (currently in poor condition, pending respray) - made in 1993
Still, I feel there's more speed to get out of this machine - probably with a newer bios (the one it runs is from 1994!!!) but I can't even find a manual for this version of the board (one with 3 VLB slots) let alone a bios.
A big thanks to everyone who gave suggestions!
