Here are some benchmarks of this chip (see several posts from skv400):
Post your 386 Speedsys results here

Anyway... if you're lucky, on 40MHz it will run at 80MHz... but that's quite a long shot as Cyrix DRX2 is 5V cpu. Your motherboard should have a 80MHz oscillator which can be replaced for a 66MHz part. Some mobos have jumpers for setting motherboard clock/speed.

kixs wrote:

Here are some benchmarks of this chip (see several posts from skv400):
Post your 386 Speedsys results here

Anyway... if you're lucky, on 40MHz it will run at 80MHz... but that's quite a long shot as Cyrix DRX2 is 5V cpu. Your motherboard should have a 80MHz oscillator which can be replaced for a 66MHz part. Some mobos have jumpers for setting motherboard clock/speed.

Impressive!! Great upgrade for the 386, but I got a Eteq 40Mhz only (sticker) chipset that I think it would not be happy changin oscillator but If I'll get one I'll try.

It's also nice to see that the 386DX-40 itself had some boost from ISA to VLB when you'd think the cpu was the bottleneck.

80MHz is a bad idea. You'll probably just fry the internal cache. Don't risk it with such a rare CPU.

80mhz is suicide don't do it or the internal cache will fail as other people have done it and have regretted it.

I accidentally did this to a Ti 486SXL-40. It runs fine at 2x25, but one time I accidentally left my 66MHz oscillator in and burned the cache. The chip works as long as the cache is disabled.

Anonymous Coward wrote:

I accidentally did this to a Ti 486SXL-40. It runs fine at 2x25, but one time I accidentally left my 66MHz oscillator in and burned the cache. The chip works as long as the cache is disabled.

Understood. I am looking for this cpu I know that it's really rare, hope to find one. At 33Mhz bus if I find a correct motherboard to set it it would be nice to see it running.

You'd probably be better off with a regular 486DLC-40, or a TI486SXL-40 (if you can find one). They're usually a lot cheaper, and provide most of the performance.