Intel i7-2600 CM8062300834302S User Manual

Datasheet, Volume 2

57

All the bits in this register are Intel TXT lockable.

15

RO

0h

14

RW-L

0b

Uncore

13:10

RO

0h

9:8

RW-L

0h

Uncore

GTT Graphics Memory Size (GGMS)
This field is used to select the amount of Main Memory that is pre-

allocated to support the Internal Graphics Translation Table. The 

BIOS ensures that memory is pre-allocated only when Internal 

graphics is enabled.
GSM is assumed to be a contiguous physical DRAM space with 

DSM, and BIOS needs to allocate a contiguous memory chunk. 

Hardware will derive the base of GSM from DSM only using the 

GSM size programmed in the register.
Hardware functionality in case of programming this value to 

Reserved is not ensured.
Encoding:
1h = 1 MB of pre-allocated memory
2h = 2 MB of pre-allocated memory
3h = Reserved
0h = No pre-allocated memory

7:3

RW-L

05h

Uncore

Graphics Mode Select (GMS)
This field is used to select the amount of main memory that is pre-

allocated to support the Internal Graphics device in VGA (non-

linear) and Native (linear) modes. BIOS ensures that memory is 

pre-allocated only when internal graphics is enabled.
This register is also Intel TXT lockable.
Hardware does not clear or set any of these bits automatically 

based on IGD being disabled/enabled.
BIOS Requirement: BIOS must not set this field to 0h if IVD (bit 

1 of this register) is 0.
0h = 0 MB
1h = 32 MB
2h = 64 MB
3h = 96 MB
4h = 128 MB
5h = 160 MB
6h = 192 MB
7h = 224 MB
8h = 256 MB
9h = 288 MB
Ah = 320 MB
Bh = 352 MB
Ch = 384 MB
Dh = 416 MB
Eh = 448MB
Fh = 480 MB
10h = 512 MB
Other = Reserved