VOGONS


The story of the QuForce FX 5800 Ultra...

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Reply 180 of 185, by Feanor_twh

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Same problem, out of range:

The attachment Dibujo.jpg is no longer available

It seems like a rogue card. Anyway, I appreciate the effort; it's a complex calculation that I'm even struggling to understand.

DOS - Amstrad PC1512 NEC V30, 640kb, 128mb CF (XTIDE)
Win3.1 - IBM PS/ValuePoint 486DX2 66, 8mb, Tseng ET4000, 2gb CF
Win98 - AT 386 case K6-III 400, 128mb, Riva TNT2 Pro, 20gb SSD
WinME - Intel Dot Station (Paquito) PIII 750, 256mb, FX5200, 128gb SSD

Reply 181 of 185, by dm-

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ask chatgpt for help, provide current values,
he will calculate new.

working for me

Reply 183 of 185, by PcBytes

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Although not a AGP card, the same BIOS + strap mod works either way apparently, at least for the G92 Quadro FX3700. I have one that I managed to convert to a 8800GT, and a 8800GT that I got to run as a QFX3700.

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Reply 184 of 185, by avenger_

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slivercr wrote on 2018-03-21, 16:10:

Rare and all, I did a voltage mod on this one: stock DDR voltage for this card was 2.3V, as far as I can tell from looking online and looking at a datasheet for "similar" Samsung chips, they should run at 2.5V. I brought them up to 2.48V, which gave me some stability when clocking them beyond 400 MHz. Easy soldering to some test points that were nearby, easily reversible too.

Nice mod. I would like to do it because it is clean and reversible.

Are there any VRAM voltage measure points on the card? How does this mod actually works? I mean how resistance corresponds to voltage?

I don't have 8,2k ohm resistor atm, the 10k is the closest one. Tried it (without soldering yet) and now I'm able to reach around 950 MHz with Ultra timings. So close to 1GHz...

Also, I'm able to reach 500MHz on 1.5V with a dusbuster-like cooler. Are these two missing capacitors on FX1000 related to core or VRAM stability? Are they really needed?

Reply 185 of 185, by avenger_

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OK, I think I've figured it out. Below is the coil where the voltage rose from 2.3V to 2.5V after I added an 8.2 kΩ resistor. With a 10 kΩ resistor, it was 2.47V. The resistor fit so tightly that I decided not to solder it in, but just secure it with a glue gun—so the mod is fully reversible.

So far, I’ve managed to reach 475 MHz/950 MHz at 1.5 V vcore and 2.5 V vmem. 500/1000 seems out of reach.