Why is my system showing 3.4gb memory extended in bios?

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Lyfer

Lyfer

Diamond Member
May 28, 2003
5,842
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81
My system seems to be showing 3.4gb extended memory and 600mb allocated to something else during the POST screen. MB is faily new, BIOSTAR amd 770 chipset. Any ideas? My secondary rig which is using an Asus 785g board shows a total of 4gb.

Is this normal?
 
Lyfer

Lyfer

Diamond Member
May 28, 2003
5,842
2
81
The system I'm having that issue with is not the one in my sig, its a different system with the HD4850 tho. Its using 2x 2gb Gskil ddr1333mhz dimms in dual channel mode. But after looking at the post screen again, it shows 3.4gb assigned extended and 620mb under "4gb+". Checked to see if there was any options in BIOS and saw none.


OS is WinXP 32bit, but I understand that XP only can see ~3gb (will be upgrading this rig to Win 7 64 bit pro as soon as I can afford another license), I dont believe this is an OS issue since that is the information being reported at the POST screen.
 
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M

mfenn

Elite Member
Jan 17, 2010
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www.mfenn.com
Lyfer said:
The system I'm having that issue with is not the one in my sig, its a different system with the HD4850 tho. Its using 2x 2gb Gskil ddr1333mhz dimms in dual channel mode. But after looking at the post screen again, it shows 3.4gb assigned extended and 620mb under "4gb+". Checked to see if there was any options in BIOS and saw none.
Click to expand...

Are you using a 64-bit OS? Does it see all 4 gigs?

What's most likely happening is that the BIOS is mapping your devices (this includes your VRAM) to to the region below 4GB in order to maintain compatibility with 32-bit OS's. Thus, there is some extra memory that must get mapped above the 4GB mark, and thus is only available to 64-bit OS's. This is perfectly normal and in fact the way ALL BIOS's handle this situation. Biostar is just kind enough to tell you what it's doing.
 
Last edited:
Lyfer

Lyfer

Diamond Member
May 28, 2003
5,842
2
81
mfenn said:
Are you using a 64-bit OS? Does it see all 4 gigs?

What's most likely happening is that the BIOS is mapping your devices (this includes your VRAM) to to the region below 4GB in order to maintain compatibility with 32-bit OS's. Thus, there is some extra memory that must get mapped above the 4GB mark, and thus is only available to 64-bit OS's. This is perfectly normal and in fact the way ALL BIOS's handle this situaiton Biostar is just kind enough to tell you what it's doing.
Click to expand...

That makes perfect sense, I guess I won't know until I get a 64 bit OS on that rig. I updated my sig with the rig information, its the 2nd system.


Thanks for all the info guys!
 
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