Mixing Different Brands of RAM

G

Guest

Guest
DIMM # 1

SMBus address 0x50

Memory type DDR2

Module format Regular UDIMM

Manufacturer (ID) Samsung (CE00000000000000)

Size 1024 MBytes

Max bandwidth PC2-6400 (400 MHz)

Part number M3 78T2863EHS-CF7

Serial number 64A196AE

Manufacturing date Week 19/Year 09n

Number of banks 1

Data width 64 bits

Correction None

Nominal Voltage 1.80 Volts

EPP no

XMP no

JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency

JEDEC #1 4.0-4-4-12-16 @ 266 MHz

JEDEC #2 5.0-5-5-15-20 @ 333 MHz

JEDEC #3 6.0-6-6-18-24 @ 400 MHz

SPD registers

00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

00 80 08 08 0E 0A 60 40 00 05 25 40 00 82 08 00 00

10 0C 08 70 01 02 00 07 30 45 3D 50 3C 1E 3C 2D 01

20 17 25 05 12 3C 1E 1E 00 06 3C 7F 80 14 1E 00 00

30 00 03 00 00 00 00 00 00 00 00 00 00 00 00 12 E3

40 CE 00 00 00 00 00 00 00 02 4D 33 20 37 38 54 32

50 38 36 33 45 48 53 2D 43 46 37 20 53 45 09 19 64

60 A1 96 AE 00 54 47 45 33 30 30 32 00 00 00 00 00

70 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

80 00 63 43 07 44 00 36 66 FE E0 47 50 01 27 0E 00

90 00 63 43 07 44 00 36 66 F0 00 36 48 00 07 0C 00

A0 00 63 43 07 44 00 36 66 FE E0 47 4E 00 04 03 00

B0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF

C0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF

D0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF

E0 45 44 4D FF FF FF FF FF FF FF FF FF FF FF FF FF

F0 01 FF FF FF FF FF FF FF FF FF FF FF FF FF FF 05



DIMM # 2

SMBus address 0x51

Memory type DDR2

Module format Regular UDIMM

Manufacturer (ID) Samsung (CE00000000000000)

Size 2048 MBytes

Max bandwidth PC2-6400 (400 MHz)

Part number M3 78T5663EH3-CF7

Serial number 9271CB16

Manufacturing date Week 21/Year 09n

Number of banks 2

Data width 64 bits

Correction None

Nominal Voltage 1.80 Volts

EPP no

XMP no

JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency

JEDEC #1 4.0-4-4-12-16 @ 266 MHz

JEDEC #2 5.0-5-5-15-20 @ 333 MHz

JEDEC #3 6.0-6-6-18-24 @ 400 MHz

SPD registers

00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

00 80 08 08 0E 0A 61 40 00 05 25 40 00 82 08 00 00

10 0C 08 70 01 02 00 07 30 45 3D 50 3C 1E 3C 2D 01

20 17 25 05 12 3C 1E 1E 00 06 3C 7F 80 14 1E 00 00

30 00 03 00 00 00 00 00 00 00 00 00 00 00 00 12 E4

40 CE 00 00 00 00 00 00 00 02 4D 33 20 37 38 54 35

50 36 36 33 45 48 33 2D 43 46 37 20 33 45 09 21 92

60 71 CB 16 00 55 57 42 35 36 30 33 00 00 00 00 00

70 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

80 00 63 43 66 42 20 36 66 FE E0 47 50 01 52 0F 00

90 00 63 43 66 42 20 36 66 F0 00 36 48 00 12 0C 00

A0 00 63 43 66 42 20 36 66 FE E0 47 4E 00 06 03 00

B0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF

C0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF

D0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF

E0 45 44 4D FF FF FF FF FF FF FF FF FF FF FF FF FF

F0 01 FF FF FF FF FF FF FF FF FF FF FF FF FF FF 01
 

bpogdowz

Distinguished
Oct 31, 2007
703
0
18,990
It doesn't matter if you change the timings in the BIOS just because it says a certain latency timing on the wrapper doesn't mean you're unable to adjust it in the BIOS. On the other hand the voltage capabilities have to be identical to avoid frying the less heat tolerant model.
 

matobinder

Distinguished
Aug 22, 2007
43
0
18,530
What brand MB is it? What BIOS manufacturer? Many "big name vendors" computers have a rather limited BIOS interface, like most all Dell's I've seen. A lower CAS latency can be faster, that is if the MB will let you set it, or it detects that. I've been out of the memory game for years. So I don't know as much on what is currently done. It at least used to be you would set your CAS, and all memory modules would use that speed. So if you had one slower one(higher number), pick the slower speed.

Really though, you have the important things listed. The "DDR2, SDRAM, 240 Pin, 1.8 Volts, 2GB"

If you don't have much control over the memory in the BIOS, there really isn't much need to buy super fancy/expensive ram. Just go with a decent brand, and be done with it.
 
For best performance, it is not a good idea to mix memory brands. If you are going to, however, relax the memory timing and really, really try to get something with the same voltage rating.
 
G

Guest

Guest
Thanks everyone. Everything checks out, it's just the Cas Latency. What number should I be looking for?