Mac Pro Crashes

[Lewis Eliou]

I have a 2008 8 core Mac Pro with 8 gig of ram . I have partitioned the drive and can run 10.5, 10.6,10.11.It has exhibited a pattern of crashing, a box will appear at no particular time telling me I need to restart my computer.Before the crash a curtain of sorts will gray the screen and then a little window appears in the middle with a restart message in several languages......but it is still a crash.I have run disk utility, from the original snow leopard disk as well, run Tech Tool and everything seems to be fine.
i did replace a graphics card about a year ago and it seems to work and test fine. anyone have experience with a crash of this kind? Please advise, Lew a pic of this monstrosity is enclosed.

 

[Cory Cooper]

Hello and welcome.

-Which exact model Mac Pro?
-Is the crashing random, or in certain applications?
-Is it reproducible?
-Does it happen on all partitions/OS X versions?

C

 

[Lewis Eliou]

It is a 3,1, with 8 cores from early 2008. Is that helpful? the crashing seems to be random . On one occasion last week crashing at start up twice in row. Today I was on the internet for about 2 hours when it crashed again. I have taken to using the option key to start and I recall once that the same thing happened in the 10.11 partition. It does seem localized to the internal drive, , My back up is a USB drive) but every tool I use says the drive is ok , no bad blocks etc.I have had occasion to be on the unit for hours ,scanning listening to itunes, and had no occurance.. My instincts are always that it is always the last thing I did. but... the last thing I did was the new graphics card . I thought it might be ram but it has checked out ok in techtool 3 or 4 times.
I have never had it happen on the 10.5.1 partition but I don't use that one all that much.