T61 "4GB DUAL CHANNEL" v.s. "6GB SINGLE CHANNEL" GPU memory

[hoax32]

Hi all!
Found a broken DELL in the trash (while i was getting rid of my trash) and decided to take it home.
To my surprise it still had MAJOR components installed in it:

250GB SATA HDD 7200RPM
1x 4GB DDR2 PC2 6400 by Hynix !!!!! <----- thats like $50 on feebay!!!
intel 4965AGN

all tested and working!!!
Now - I use my T61 primarily for 3D software including Blender and Modell Simulators, which require ALOT of GPU power.
My NVS140m is custom cooled and overclocked %75. [CORE@706MHz MEM@980MHz SHADER@1650MHz]
After 1 hour of Video Load temps cap at 80*C.
Since the GPU MEM BUS is only 64BIT, OCing the MEM CLOCK helped ALOT.
But I also rely on the Dual Channel Mode of the DDR2 for the shared memory speed.
Now - i don't know if i should install the 4GB Module and give up dual channel....
Does the Shared memory even utilize Dual Channel Speed from the Main Memory? [it should, right???]

[ajkula66]

But I also rely on the Dual Channel Mode of the DDR2 for the shared memory speed.
Now - i don't know if i should install the 4GB Module and give up dual channel....

I don't understand.

Install 4GB in one slot, and 2GB (or whatever you have available) in the other.

That's going to run as dual-channel...

[hoax32]

I don't understand.

Install 4GB in one slot, and 2GB (or whatever you have available) in the other.

That's going to run as dual-channel...

DC requires same module speed & often [not always] also the same size
imfact it happens that 2 modules are so different, that a system wont even post [usually on old early hardware]

[ajkula66]

DC requires same module speed & often [not always] also the same size
imfact it happens that 2 modules are so different, that a system wont even post [usually on old early hardware]

This is incorrect.

Your PC2-6400 will downclock to the PC2-5300 speed and here's your dual channel mode.

The laptop will be running in the asymmetric mode, but the loss incurred when compared to a fully symmetric mode is beyond human perception.

BTW, I've *never* encountered a machine failing to post due to two different speed DIMMs, as long as they were compatible with it in the first place.

[hoax32]

This is incorrect.

Your PC2-6400 will downclock to the PC2-5300 speed and here's your dual channel mode.

The laptop will be running in the asymmetric mode, but the loss incurred when compared to a fully symmetric mode is beyond human perception.

BTW, I've *never* encountered a machine failing to post due to two different speed DIMMs, as long as they were compatible with it in the first place.

i do not get dual chanel with the 2 + 4GB pc6400 modules... (both 6400) probably cause of size difference and chip aarangement....but i do get DC with both 2GB DDR2.....idk why 2 PC6400 modules would downclock to 5300.....and when i used to have 2GB DC pc5300, i got lower frames in GPU stress tests.
thats why i upgraded to 6400 in first place, which gave me ~ 4 extra frames in 3D Mark 05
[THERE IS A BIG DIFFERENCE IN SHARED MEMORY SPEED]

[ajkula66]

idk why 2 PC6400 modules would downclock to 5300.....

That is the speed applicable to your motherboard, correct?

When using two DIMMs of different speed, they always downclock to the speed of the slower one.

[Cigarguy]

Since you already have everything there. Try a few combo and go with the one you think is fastest or benchmark the fastest. I ran into a similar dilemma a while back. Sold my 2x2 GB sticks and bought another 1 x 4 GB stick to pair with the single 1 x 4 GB I had. Not that I needed the extra 4 GB. Just wanted to have it.

PS - My combo of 1x2 GB and 1x4 GB showed dual channel on CPUZ. My T61 was running fine but for some reason I (the dumb user) felt unbalanced.

[miro_gt]

i do not get dual chanel with the 2 + 4GB pc6400 modules... (both 6400) probably cause of size difference and chip aarangement....but i do get DC with both 2GB DDR2.....idk why 2 PC6400 modules would downclock to 5300.....and when i used to have 2GB DC pc5300, i got lower frames in GPU stress tests.
thats why i upgraded to 6400 in first place, which gave me ~ 4 extra frames in 3D Mark 05
[THERE IS A BIG DIFFERENCE IN SHARED MEMORY SPEED]

yes you do get dual channel, but its asymmetric.

your MB only supports 667MHz DIMMs so if you put 800MHz DIMMs then those would downclock to 667MHz speed (i.e. the PC-5300)

the upgrade to PC-6400 was not what gave you extra frame rates, as it downclocked to PC-5300 frequency anyways. However, the timing of the modules at 667MHz may have been lower thus you saw small difference in the frame rate. Besides, your testing may be off in accuracy as it is highly dependent on what the laptop is doing at the time of the testing, i.e. other processes may interfere. You have to run multiple passes of the test to determine the average speed, and only then you can confirm that something made a difference.

on a side note, fastest memory modules that you can put in a T61 are made by G.Skill and come with 4-4-4-12 timing, 2GB each. I use those in both my laptops. Anything faster than that has to be custom programmed and is no guaranteed that will work stable. So you cant put more than 4GB RAM with 4-4-4-12 timings as 4GB modules with such timings dont exist.

[ac12]

The other thing is your 32bit OS won't see anything above 4GB. So unless you upgrade to 64bit OS, the extra 2GB is not usable to you.

[hoax32]

thats an old signature - running 64bit
ima test 2day

[Thrakath]

If you overclock the GPU-RAM cool it!!!! I fried my NVS140M with clocks below yours and one corner of the Chip melted on the PCB. Check it out, it´s below the Wlan Card!

[hoax32]

its BARELY warm :/
you talking about the HYNIX memory chip next to the modem and wifi card?
GPU temps cap at 79*C after hours of use.

EDIT: before i forget - I do have a somewhat custom cooling in this T61 and I removed the modem to get rid of extra heat and power consumptiop + ventilation.
ALSO THIS IS A LATE PRODUCTION T61 wit the more heat resistent material

[Thrakath]

You cannot conclude your RAM-temps from your GPU Core. Imagine it´s below another heater, the Wifi consumes up to 5W! Finally it´s your risk. in my 4:3 i tried to move the Wifi Card in the 2nd PCIe Slot close to the CPU but the cables were 1-2mm too short. Maybe it works for you!

[hoax32]

as I stated above - the only memory chips that i found (hynix chips next to GPU) - are barely warm to the touch.
can you provide me with a picture of the same chip that melted on your t61?
[hab vergessen bitte zu sagen ]

[Thrakath]

No sorry didn´t keep the old mainboard. It´s the hynix memory chip and at least for the 128MB board it´s only this chip and nothing on the bottom side of the mb. So when did you measure the chip´s temp? Played Doom3 with removed keyboard?
And keep in mind: As soon as you remove the keyboard + Wifi you already create an artificial condition because heat transfer can take place compared to everything mounted. Only good possibility to measure properly would be an electronic thermometer with an external sensor mounted on the hynix.

[Raceboy]

One can use a regular NTC thermistor with 2 kOhm nominal to measure whatever temperature he/she wants. Just measure the reistance and using 2 kOhm nominal resistance it is possible to determine real temperature. This is the way all the temperature sensors on the engines work for example (there are PTC ones also, these are just reversed).

[hoax32]

after running furmark for hour, the chip is about as warm as the heatsink [maybee 40*C] ????
Tested it with a removed keyboard.