VOGONS


First post, by GabrielKnight123

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I just picked up 8 CL GD5428 cards but they all have what looks like 1mb of vram with 2 banks empty, is it possible to mooch/harvest 2 banks from one card and fill another card to Max out the vram to 2mb?

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Reply 3 of 8, by mkarcher

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GabrielKnight123 wrote on 2021-10-31, 11:38:

I just picked up 8 CL GD5428 cards but they all have what looks like 1mb of vram with 2 banks empty, is it possible to mooch/harvest 2 banks from one card and fill another card to Max out the vram to 2mb?

The kind of chips used by that VGA card are the standard kind of RAM chips used by most 512KB and 1MB VGA cards, the Gravis Ultrasound (classic), some kind of Laser printers, early 286 and 386 mainboards and other stuff common around 1989-1994. If the chip physically fits and the model number contains "4256", it will work. The only thing you need to take care of is not inserting the chip the wrong way around. This might easily break the chip, although I already got lucky twice with reversed (ROM) chips which were not blown by reversing them (On the other hand, I lost a 1024KBit Cache SRAM chip to reverse insertion, so the danger is real).

Chips harversted from old 256KB VGA cards usually contain "464" in the type number and do not work.

Reply 5 of 8, by Imperious

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I recently got one of these cards, an Acer branded one with 2 512k EDO memory chips in bank 0 that also are 70ns. I added 8 70ns ics in bank 1, works perfectly.

There are 2 banks in total, usually 8 chips in each except for cards like mine that uses 2 edo memory ics in bank 0.
I still get 28.1ps in doom with a dx2-66 and 7.8 in quake dos.
I was half expecting a performance hit but fortunately that didnt happen.

Atari 2600, TI994a, Vic20, c64, ZX Spectrum 128, Amstrad CPC464, Atari 65XE, Commodore Plus/4, Amiga 500
PC's from XT 8088, 486, Pentium MMX, K6, Athlon, P3, P4, 775, to current Ryzen 5600x.

Reply 6 of 8, by Anonymous Coward

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Most. Useless. Upgrade. Ever.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 7 of 8, by rasz_pl

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Upgrading to 2MB will get you access to two additional interlaced modes and zero performance difference.
Not so secret secret: Cirrus Logic GD5428 has 16-bit host interface. Its the miracle of engineering (deep fifo?) its as fast as it is in VLB form.

Open Source AT&T Globalyst/NCR/FIC 486-GAC-2 proprietary Cache Module reproduction

Reply 8 of 8, by mkarcher

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GabrielKnight123 wrote on 2021-10-31, 23:59:

Thanks all, all the chips in this card are 70ns speed did they ever use 60ns chips?

The maximum specified memory clock of the 5428 is 50MHz. 70ns is fast enough to support this clock, at least if the card is configured to add a single wait cycle in the case of page misses. Due to the FIFO buffers, page hits are the common case, and this wait state is hardly noticeable. The 5429 increased the maximum specified clock to 60MHz and may profit from 60ns RAM.