Scan embedded video memory

[bdb]

Hi there all,

I have some difficulties with a notebook of mine.
I have a hard time finding the problem, 19 passes 0 errors. I'm thinking about the video memory which is embedded.

Q:
Does memtest also check this (embedded video) part of the memory for errors, or is this impossible due allocation.

Is it a feature, a lack or a future feature

Thanks bdb

[David (PassMark)]

Video RAM is not tested by MemTest86.

There are no plans to add this. It isn't a trivial exercise to get access to the video RAM when no operating system is loaded, plus some of the video RAM is actually used by the video card for maintaining the display.

BurnInTest can test some of the video RAM from within Windows however (from the 2D graphics test options).

[bdb]

Thanks for your reply

Windows doesn't run, I think due a hardware malfunction, I might try the burnintest later when it is up and running.
I don't understand your full statement, the impossibility of scanning memory which is assigend at that moment to the video clear though.

Thanks a lot

[David (PassMark)]

There are various types of video cards. Some have their own RAM and some share main memory.

In the case where main memory is allocated to the video card, it isn't safe for the CPU to directly read and write these memory address. The likely outcome would be video display corruption and a crash.

The normal process (when an operating system is running) is that an application makes a request to DirectX for a video RAM buffer, DirectX then makes a request to the video card device driver. The video card device driver determines what video RAM is free and allocates a buffer back to the application (for the CPU to use).

[bdb]

Thanks to your replies I think I'm starting to understand the working of the ram.

I think the video of this notebook uses a part of the ram, and I know by now this part can't be scanned for errors.
I switched rambank 1 into slot 2 and vice versa, and restarted memtest for one night, because I assume that the bios allocates always the same part of the memory bank (for example first part of bank in slot 0)

After 8 passes and zero errors I think, I can conclude the ram is fine, and the video ram two (as far as it uses the ram banks)

Thanks a lott