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View Full Version : NEC V20 - What games will it let my XT run that it couldn't before?



Raven
May 7th, 2010, 05:08 PM
Question is in the title.. I tried running the VGA version of DIGGER again once I upgraded my XT with the V20 I found in an old (very dead) XT I had lying around that I was going to can due to irreparable damage (also saved the ROMs and some memory chips.. pretty much anything socketed).. Anyway the V20 made little if any difference in running DIGGER at full speed. I realize that the CGA version should run plenty fast on this machine, but according to my research, the VGA version was created because the CGA version was incompatible with anything but a proper CGA card, and I don't have a color monitor for mine (yet). Now I'm chocking that up to the specific game, and was curious what (if any) games people have convinced to run acceptably using a V20 on an XT?

pianoman72
May 7th, 2010, 08:14 PM
Times of Lore should run very well on a V20. Although I haven't tested that game on the V20, I did run it on both a stock IBM XT @ 4.77mhz, as well as a Packard Bell 286 @ 8mhz. The CGA version runs perfect on the XT, but, in changing the video card to a VGA adapter on the same system, it runs quite slowly. I don't know if putting a real EGA card (with its accompanying monitor) might work better, since the EGA mode would not be emulated, as it is on a VGA card. Conversely, running the game in VGA on the 286@8mhz is a bit too fast, but manageable.

digger
May 8th, 2010, 02:18 AM
I didn't notice any loss of compatibility when we upgraded the 8086 CPU in my Dad's M24 to a V30. But then again, the 8086 in the M24 ran at 8MHz, so any games that required an exact 4.77Mhz clockrate for timing reasons would not have worked properly on it to begin with (although I've never encountered an PC/XT era game that would not work on that machine at all).

Anyway, one thing I did notice was how some visual details suddenly became visible on that machine after the V30 upgrade. For instance, in the CGA/EGA version of Monkey Island 1, in the SCUMM Bar, the drunk pirate hanging on the chandelier was hanging still with an 8086, and actually swinging back and forth all the time with a V30 installed. I saw similar additional animations in Space Quest III. I assume that these games simply checked for the existence of the (real-mode) 286 instructions to make sure the machine was fast enough to show the extra (parallel) animations without slowing down the gameplay too much. Since the V20 and V30 processors also have these additional instructions, the games assume that they are running on a 286-class machine and enable those on these CPUs as well. Fortunately, the additional speed of these upgrades appeared to compensate nicely (at least in my experience) for the additional burden of these extra animations.

Anyone else noticed such improvements in other games as well?

Marrr
May 9th, 2010, 07:46 AM
There's V30 port of Wolfenstein 3D somewhere, very likely runnable on a V20 as well, but I wouldn't expect much playability here...