View Full Version : Basic rez question

02-05-2002, 06:24 PM
I have an Apple VRAM Expansion Card with four 256k VRAM modules in my 6110 upgraded to a G3/333. At thousands of colors I can get a resolution of 1152 x 870 @75Hz where the images seem compressed (I think I can tweek the monitor for this) and 1024 x 768 @74.9Hz with no distortion.

At millions of colors I can only get undistorted images at 832 x 624 @ 75Hz. Set to 1152 x 870 @75Hz I get mouse trails and at 1024 x 768 @74.9Hz I get severe ghosting in triplicate.

The monitor documentation claims to support the higher resolutions. Any suggestions or is that as good as it gets with his vintage machine.

02-05-2002, 08:07 PM
A couple of things to try:

1. Try reseating your VRAM chips - not having them seated properly can lead to visual artifacts - I noticed that on a 7500 before when I was playing around with the VRAM.

2. Are you using any adapters to connect your monitor to the card? If so, do you have other ones (or a friend's) you could use to test? I doubt it would be an adapter problem, but I'm just thinking of possibilities.

3. On upgraded vintage-PCI Macs, video artifacting is evidently a not-so-rare problem. However, my parents use a G3/260-accelerated 7100 (NuBus) without any video problems.

02-06-2002, 07:56 PM
Thanks. I did TechTools Pro check and it told me the vram was ok but I'll try reseating them anyway. The adapter might be a good bet because it's a non-dip switch type which may only support specific resolutions. I obtained a dip swith adapter and I'll experiment with that.

02-07-2002, 02:07 PM
The VRAM expansion card is also called the HPV card. The HPV card came in two varieties. The first shipped in 6100s and 7100s and came with 1 MB of VRAM soldered down and slots to add another 1 MB for a total of 2 MB. We'll call this the 2 MB HPV card. The second shipped in 8100s, had 2 MB of VRAM soldered down, and has slots to add another 2 MB of VRAM for a total of 4 MB of VRAM. We'll call this second card the 4 MB HPV.

Both cards have four identical SIMM sockets on them. However, on the 2 MB HPV you add four 256K VRAM modules to get 2 MB total. On the 4 MB HPV you add four 512K VRAM modules to get 4 MB total. No other VRAM modules are supported.

If you added four 256K VRAM modules then you should have the 2MB HPV. However, I'm pretty sure that 2 MB of VRAM only supports millions of colors up to 832 X 624. So, you should not even be able to get millions of colors above 832 X 624 with the 2 MB HPV card.

It is possible that what you actually have is the 4 MB HPV card. If that is the case then you have 3 MB of VRAM right now and so you are sort of able to get millions of colors at the higher resolutions. However, you have the wrong VRAM modules installed in it and that is why you are getting strange artifacts.

The last paragraph is my best guess about what is going on here. You need four 512K VRAM modules.

02-07-2002, 03:26 PM
Well that adds a new wrinkle I didn't consider. I have two other exact cards in front of me. Would there be any indication on the card that would indicate the correct vram module? All of them say Bt9055 RAMDAC 100 1993 Apple. There are several other numbers written on them as well.

02-08-2002, 03:18 AM
I don't know how to tell them apart by inspection. Try installing the card with no VRAM modules installed. Now, if you can get 832 X 624 at millions of colors then you have the 4 MB VRAM card, because 2 MB of VRAM is enough to do 832 X 624 and millions, but 1 MB of VRAM is not enough to do millions of colors at 832 X 624.

02-08-2002, 04:16 AM
Difference between the two HPV cards:

7100 - Apple part #661-1748 (Serial Number 820-0522-xx) http://www2.sunrem.com/sun02.w?pt=661-1748&catcode=14520

8100 - Apple part #661-1027 (Serial Number 820-0509-xx) http://www2.sunrem.com/sun02.w?pt=661-1027&catcode=14720

My recollection is that the Apple Part Number is not on the card but the Serial Number is the key and is located in the bottom right corner of the card. k

02-08-2002, 07:41 PM
Kaye.....Bravo! From the serial numbers I was able to determine that one of the extra cards I have is from a 7100 and the other is from an 8100. I'm willing to bet the card I installed is for an 8100 which means it has the wrong VRAM. I'll know for sure when I get home tonight. One difference in appearance between the cards is that the VRAM slots on the 7100 card are white while the slots on the 8100 card are black. I don't know if this is significant. I'll let you know how I make out.

02-10-2002, 05:06 PM
It was the card indeed. I installed the 7100 card with the correct VRAM modules and I'm able to get thousands of colors up to 1152 x 870 and millions of colors up to 832 x 624. The best result is at 1024 x 768. I assume I would need the increased VRAM on the 8100 card to get millions of colors at that resolution but I'm satisfied with the way it is, a vast improvement over the built in video. Thanks to all for your help.

02-10-2002, 09:43 PM
HPV cards:


All of the above at Millions