Thinkpads Forum

I did a search but didn't find what I was looking for. I got the T61p with the 14" screen (Nvidia Quadro 570 with 128Mb memory). I have read in a couple of places that the memory bus of the 128mg chipset (14") is half that of the 256Mb chipset (15") - 64bit vs 128bit. In one post, it was said that the 128Mb system was clocked twice as fast as the 256Mb system, giving the same overall memory bandwidth.

Anybody have a definitive answer on this or know where I can get the real skinny?

Bus width x Freq = Bandwidth

So 128 bits x 300 MHz or 64 bits x 600 MHz, bandwidth is just the same.

Yes, if bus is half and the memoroy clock is twice, the bandwidth is the same. So my question is, can anbody confirm that the bus is half and/or the clock is twice on the 14" screens vs the 15" screens?

Anyone????? Bueller?????

I've heard those, too, and would like a definitive answer. Also, is there any performance difference between the two configurations (half width, double frequency versus single width, single frequency), all other things being equal?

I don't remember where I found it on the net. A chinese website shwo picture and bench. T61p have two memory chip (one on each side of the main board). The datasheet from the chip tells 128 MB 128 bits. So, two gives a 256 MB with 256 bits bus. T61p 4/3 have only one 128 MB 128 bits chip (upside on the mainboard).

I'am sure 100%. I post a link last year about this.

Unless there are other changes into it, more memory chips will not extend the data bus width. I.e. a 128 bit 1x128 MB has the same width of 2x128 MB.
Or ?

Actually, what I read was the 15" screen T61p had two 128mb memory chips each with 64mb bus (2x128 = 256Mb RAM, 2x64Mb bus = 128Mb bus), while the 14" had a single 128mb chip with a single 64Mb bus. While the 128Mb 14" model was (supposedly) clocked twice as fast, for the same bandwidth, the 256Mb 15" mode still has twice the GDDR3 video memory.

Oups I make a mistake about the bus sizes. It's 64 and 128 not 128 and 256. I'am sorry. Most time, I care about desktop products and 64 bits bus belongs to old time.

Yeah, that's why I was bummed when I read this - 64bit memory bus - so 2003! And that's why I really hope the clock speed is doubled, but I can't find any official verification of this.

Wouldn't one of those nvidia tweaking/overclocking tools show the memory clock? Or do they just show the core?

RivaTuner : core, shader and memory
ATItool : core and memory
Everest : core and memory

Excellent point. Why didn't I think of this

GPU-Z can also display usefull informations but it requires Microsoft .Net framework.