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!
If will you be online then please provide pic of your config.
Couldn't manage 512K cache.
With 256K there was error in your jumpers description:
256kb Cache - JP21 open| JP20 closed | JP19 closed
256K proved by cachechk.
