Best Passive Radeon for Groovymame OS ?

[akumajo]

Hi

I'm thinking about a new different build with GroovyMame Linux OS and I would like to know which video card is recommanded ? Still a Radeon (no Nvidia?).
It must have 15khz support, passive, pci-express, vga output.

It seems that Radeon x600 is a good challenger.

Only for 2d games.

Thanks.

[Calamity]

The Radeon X600 is a sure bet. New GroovyArcade (coming soon) is going to support NVidia experimentally, in case you want to test.

[akumajo]

any nvidia ?

[Calamity]

any nvidia ?

Probably not, who knows... The NVIDIA support is based on the Nouveau driver, so that will depend on which chipsets are supported by this driver, I guess. I've not tested it.
 

[akumajo]

Ok, I was told that 4350 Radeon was the first radeon which support true 320 x 240 ?!
What does it means ?

[dgame]

Are there any issues using the cards newer than the 4350 in regards of low dot clocks? I seem to recall from my days using soft-15khz that the 4350 was the last card produced to achieve low dot clocks...??

Good question.  The way I understood it, the dot clock limit is based on the actual design of the card and the components used, not the specific chip, though could be wrong.

I wonder if there's any way to test the dot clock and start some sort of list of cards (by exact model number) with low dot clocks.

According to the experience with Linux (and the patches done by bitbytebit), the dotclock lower limit seems to be software related. There's probably no physical limitation of the hardware that prevents it from getting lower dotclocks. But drivers limit achievable dotclocks between some upper and lower limits they get from the videocard's rom (not always).

A dotclock is a frequency value. When you request a given dotclock to the driver, it needs to program the PLL dividers, in order to convert the videocard's master clock frequency (i.e. 400 MHz) into the frequency (dotclock) we are requesting. It's an arithmetic problem. Drivers contain specific algorithms to achieve that, which depend on the chipset. So some chipsets may work better with some values than others. The problem here is that not all achievable dotclocks are stable, so picking the right algorithm is critical as this is a common source of troubles for driver developers it seems.

Now, for older ATI cards I've tested (R 9250, R X300), even if they're BIOS sets a limit for their lower dotclocks (which required a specific patch in GroovyArcade), that value seems to be happily ignored by Windows drivers, which admit nearly any imaginable dotclock for these cards.

The problems started with later models of the X family, and for the whole HD 2000 and HD 3000 families. For those cards, Windows drivers seem to use a dotclock's lower limit of around 7 MHz. That makes them not the best choice for emulation, as they will refuse to work with resolutions lower than 384x or 400x, unless you set huge porches to artificially increase the dotclocks required. Fortunately we can still use these cards by creating modes with double width, so Mame will scale the frame and the result will be perfect. But anyway, it's better to pick one card that can natively do really low resolutions, as there are more emulators other than MAME that may not be so smart.

Fortunately, HD 4000 family can, again, do any low dotclock, as it was the case of older cards. We don't have patched drivers for anything above HD 4000, and probably won't, so one card of this family is the best choice if you wan't to have a full working 15 KHz card while still have a relatively modern (or not so ancient at least) card.

Probably that 7 MHz limit of the other cards could be unlocked by patching the Catalyst video drivers, but that could (or could not) be a collosal task, and after all you can get a more modern card from the HD 4000 for a few dollars.

[lettuce]

The Radeon X600 is a sure bet. New GroovyArcade (coming soon) is going to support NVidia experimentally, in case you want to test.

Is an X800 or X1950 (or though im not sure if theres a passive version) suitable aswell?

[Calamity]

Is an X800 or X1950 (or though im not sure if theres a passive version) suitable aswell?

I don't think so, I believe the highest model from X series that accepts low dotclocks is the X600. However, those cards (X800, X1950) should be usable as long as you scale resolutions horizontally (GM does this transparent to the user). For other emulators things wouldn't be so easy.

[iori01]

Hi Calamity

when you say 'Nouveau driver of NVIDIA is supported', do you mean that Nvidia will have tweaked driver ? based on 3xx driver series ?

In any case , thanks for your amazing job 

[Calamity]

Hi Calamity

when you say 'Nouveau driver of NVIDIA is supported', do you mean that Nvidia will have tweaked driver ? based on 3xx driver series ?

In any case , thanks for your amazing job 

No teaked driver for Windows if that's what you mean.

I mean NVIDIA cards should be supported by GroovyArcade LINUX, starting from next release. Thanks to VeS for implementing this, he's been doing basic testing with on NVIDIA card (can't remember the model he said) and it seems to work. We can't promise it will work for all NVIDIAs out there.