VOGONS


Reply 40 of 47, by Kahenraz

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I ran some tests with Quake 1 on a fast Pentium D 3.4Ghz, to rule out any CPU bottlenecks. There was some kind of incompatibility with the GeForce FX series cards (PCI/PCIe), but performance was consistent when tested with a Voodoo 4 4500 PCI and a Radeon X300 PCIe.

The test results were as follows:

66 Mhz - 29.9, 30.8
75 Mhz - 32.6, 33.6
80 Mhz - 35.9, 36.0
90 Mhz - 39.3, 39.6

These tests were run at 640x480x16. Performance was consistently higher than with 32bit.

Performance seems to be pretty linear with clock speed for this test. This is very promising. I don't have any faster clock crystals to test with beyond 90 Mhz.

I didn't experience any graphical corruption or anomalies at any clock speed.

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Reply 43 of 47, by Babasha

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Kahenraz wrote on 2022-06-06, 00:22:
I ran some tests with Quake 1 on a fast Pentium D 3.4Ghz, to rule out any CPU bottlenecks. There was some kind of incompatibilit […]
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I ran some tests with Quake 1 on a fast Pentium D 3.4Ghz, to rule out any CPU bottlenecks. There was some kind of incompatibility with the GeForce FX series cards (PCI/PCIe), but performance was consistent when tested with a Voodoo 4 4500 PCI and a Radeon X300 PCIe.

The test results were as follows:

66 Mhz - 29.9, 30.8
75 Mhz - 32.6, 33.6
80 Mhz - 35.9, 36.0
90 Mhz - 39.3, 39.6

These tests were run at 640x480x16. Performance was consistently higher than with 32bit.

Performance seems to be pretty linear with clock speed for this test. This is very promising. I don't have any faster clock crystals to test with beyond 90 Mhz.

I didn't experience any graphical corruption or anomalies at any clock speed.

Screenshot_20220605-202734_Chrome.jpg

Thank you! Very interesting

Need help? Begin with photo and model of your hardware 😉

Reply 44 of 47, by JustJulião

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Kahenraz wrote on 2022-06-04, 19:18:
Tested working at up to 90 Mhz. This larger heatsink keeps the chip quote cool. […]
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Tested working at up to 90 Mhz. This larger heatsink keeps the chip quote cool.

I haven't heard anyone overclocking a PCX2 this high. It works great.

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I struggle to find a 90Mhz oscillator. Where did you find it ?
I'd be interested by the socket's reference too. For now I couldn't find one as modular as yours.

Reply 45 of 47, by Kahenraz

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I got ordered this crystal from a seller on AliExpress that specializes in them. I'll see if I can find it for you. At the time, I wanted to order other speeds, but this was during the height of the pandemic and he didn't know when they would be back in stock.

This particular layout is by VideoLogic. The other layout is by Matrox. There are different revisions of the VideoLogic PCB, with some slight component variation, but they are all pretty much the same.

What is different about yours? Can you share a photo?

Reply 46 of 47, by JustJulião

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Kahenraz wrote on 2022-06-20, 18:09:

I got ordered this crystal from a seller on AliExpress that specializes in them. I'll see if I can find it for you. At the time, I wanted to order other speeds, but this was during the height of the pandemic and he didn't know when they would be back in stock.

This particular layout is by VideoLogic. The other layout is by Matrox. There are different revisions of the VideoLogic PCB, with some slight component variation, but they are all pretty much the same.

What is different about yours? Can you share a photo?

Thanks for your reply.
This is this one Saving a PowerVR card
I meant your socket with multiple choices, it's really convenient. I admit I didn't search for very long but I know nothing about electronics (though I know how to solder/desolder).

Reply 47 of 47, by Kahenraz

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These are solderable pin headers. I removed the old crystal and added the pin headers so that I could easily swap in new crystals for testing.

Here are some photos of the part. I've also included an eBay listing, but you may be able to find it cheaper elsewhere. I just did a quick search for you.

https://www.ebay.com/itm/373833415253

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