On Saturday, Mar 1, 2003, at 10:01 Europe/London, Powermac wrote: > I just added 4x256k vram to my 840av and it works fine. Must be 80ns > vram to > work, alot of the older quadra's can use 100ns ram but not the 840. I > think > what your seeing is a marginal vram stick and video corruption i the > area > where data is held on that stick. Try rearanging the sticks in the 4 > slots > and see if the image corruption changes to another area.
I have had this problem with VRAM in PCI PowerMAcs. I had a 7500 and a 7300 and the VRAM worked in the 7500 and not the 7300 (both in OS X 10.1.5). It seems to be a weirdosity that some Apple machines have. It may be that there is a bad VRAM chip in there but it only manifests itself on an 840av due to the speeds and stresses the 840av puts thru the video system. > 4x512k wont work in the 840. Some machines like the Q950 will take the > 512k > vram but only use 256k of each stick. 512k SIMMs are usually recognised as 256k on an 840av. I think there are 1 or two 512ks that don't work properly. > do you see a -80 on the chips? or -8 or a number xxxx80 or xxxx8. *Generally Speaking* 512k VRAM SIMMs have 4 large chips on, and 256ks only have 2 on one side. This is not an absolute but it's what I generally find in my large crop of variously upgraded LCs. -- Mark Benson AIM - SilValleyPirate Visit FlatPackMacs online: <http://fpm.68kmac.com> Visit my Homepage: <http://homepage.mac.com/markbenson> Vintage Macs List Nanny "Never send a human to do a machine's job." -The Matrix -- Quadlist is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! | Support Low End Mac <http://lowendmac.com/lists/support.html> Quadlist info: <http://lowendmac.com/lists/quadlist.shtml> The FAQ: <http://macfaq.org/> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/quadlist%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
