I doubt any card will be endangered. More complex ones like graphics cards have own clock source, so it is only question whether they will tolerate the bus clock.

Can't say too much on the specific question since I don't know the mainboard and graphics card - but keep in mind your boost is almost 25% which isn't so small if you think about it.
I'd say if it survives a 1 hour burn-in it should be good to go.

My experience is that even 41.5 MHz (83/2) is fine with almost all hardware while 44.3MHz (133/3) often cause issues with disk controllers and disks.

I managed to fry a PCI Realtek NIC once while on an OC/benchmark binge, where I overclocked the PCI bus too. Still not sure if that's what caused it, but I do know it did work before, and it no longer did after that.

edit: 1337th post!!! 🤣

I've been using the PVI-486SP3 with a 40 MHz bus for years and the speed boost with video cards is really worth it. I had problems with network cards though, it took me a while to find a 3com NIC that tolerated the overclocked bus.

If your only PCI card is a graphics card, there are no problems to be expected except for maybe an occasional harmless video glitch. However, if you use PCI cards like NICs or harddisk controllers, you might encounter errors which are hard to detect but have annoying consequences, like network transfer errors or corrupt filesystems.

5u3 wrote:

I've been using the PVI-486SP3 with a 40 MHz bus for years and the speed boost with video cards is really worth it. I had problems with network cards though, it took me a while to find a 3com NIC that tolerated the overclocked bus.

If your only PCI card is a graphics card, there are no problems to be expected except for maybe an occasional harmless video glitch. However, if you use PCI cards like NICs or harddisk controllers, you might encounter errors which are hard to detect but have annoying consequences, like network transfer errors or corrupt filesystems.

Thanks for the feedback. In a different post on the PVI-486SP3 motherboard you mentioned that applying BIOS revision 3.07 (beta) caused other bugs (although it solved the Y2K bug issue). What were those bugs?

Just beware that onboard controllers might be using the PCI bus, so even if your only PCI device it's a graphics card, you might have other devices on the bus that might give you trouble

I noticed that the video card (S3 ViRGE) runs a little warmer on 40MHz compared to 33
but not dangerously so. It's stable enough at 40MHz. I doubt you will do any damage.

alexanrs wrote:

Just beware that onboard controllers might be using the PCI bus, so even if your only PCI device it's a graphics card, you might have other devices on the bus that might give you trouble

Yes, that was also something that came to mind after my initial post.
I forget to mention that the motherboard I referred to also has one VESA local bus slot.
Read something about bridging between the PCI slot and the VESA local bus slot but, I don't know how overclocking will impact this.

On the PVI-486SP3, the onboard CMD640 IDE controller does not show up in PCI device lists (e.g. Speedsys has a PCI device list feature), so it seems to be connected via VLB.

Isn't VLB even more finicky than PCI when it comes to overclocking?

alexanrs wrote:

Isn't VLB even more finicky than PCI when it comes to overclocking?

If memory serves correct, I think that up to 40 MHz is still part of the VLB specification. With PCI, only up to 33 MHz is part of the standard specification.

The 5x86 I was given as a gift two years ago was working at 150MHz (3x50MHz FSB) without PCI divider. It has been at this state for several years. The previous owner added a crude aluminium heatsink from a radiostore and made a custom VGA cooling system, but except for that, it was stock. The motherboard was a 4DPS clone, the videocard was an S3 Trio 32.