- Sep 23, 2011
- 2,023
- 275
- 126
http://www.pcper.com/reviews/Mobile/Nvidia-GeForce-GT-640M-Review-Kepler-Arrives-Mobile
so....charlie wasn't THAT wrong =P
so....charlie wasn't THAT wrong =P
3D Mark 06: 9591
3D Mark 11: 1785
DoW 2: 44.53
JC 2: 53.25
BF 3: 45.21
3D Mark 06: 12176
3D Mark 11: 1449
DoW 2: 60.62
JC 2: 56.8
BF 3: 39.18
http://www.pcper.com/reviews/Mobile/Nvidia-GeForce-GT-640M-Review-Kepler-Arrives-Mobile
so....charlie wasn't THAT wrong =P
NVIDIA GeForce GT 555M "A"
96 CUDA Cores, 16 TMUs, 4 ROPs, Core Clock: 753MHz, Shader Clocks: 1506MHz
128-bit Memory Bus, GDDR5, Effective Memory Clocks: 3138MHz
Desktop Counterpart: GeForce GT 440 GDDR5 (GF108)
And this is where NVIDIA's mobile lineup completely loses its mind. The GeForce GT 555M is actually two completely different chips and configurations; the "A" and "B" are our designation. Our "A" configuration is essentially just a souped-up version of the GT 525M/540M/550M, with a higher core clock and the benefit of GDDR5. While NVIDIA lists both versions on their site (though lacking an explanation as to why this split was made), a glance at NewEgg suggests this "A" version is the more common of the two (powering MSI and Lenovo laptops while the "B" version resides almost exclusively in an Alienware.) You can recognize the "A" version by the use of GDDR5, but since it and the "B" version are so bizarrely matched we can't really tell definitively which one would be the faster of the two. (No review available.)
NVIDIA GeForce GT 555M "B"
144 CUDA Cores, 24 TMUs, 24 ROPs, Core Clocks: 590MHz, Shader Clocks: 1180MHz
192-bit Memory Bus, DDR3, Effective Memory Clocks: 1.8GHz
Desktop Counterpart: None (GF106)
The other configuration of the GT 555M is a substantially beefier chip with six times the ROPs, but it operates at lower clocks and lower memory bandwidth due to the use of DDR3 instead of GDDR5. It's essentially a die-harvested version of GF106, and is identifiable by both the use of DDR3 and memory configurations of either 1.5GB of 3GB. It remains inexplicable why NVIDIA decided to use two completely different chips for the GT 555M, but hopefully this makes it a little easier to tell which is which. Raw calculations of pixel and texture fillrate suggest this "B" configuration to be the faster of the two, and as such it's probably the one to look for. Thus far we've only seen it in the Alienware M14x. (No review available.)
So taking the BF3 results, the new shaders are ~1/3 as effective as the old shaders (taking into account clock speed differences).
Extrapolating this to gk104 vs gtx580, it has 3x more shaders which run much faster. It could well be gtx580 +20%, which puts it right into 7970 territory at stock.
That's excellent for a chip of its size.
I am 90% sure that this particular laptop has ddr3 ram strapped with that 640m, no doubt hindering it.
I feel slightly confused, but how did you reply to a post that comes after yours considering that it does not indicate that your post was edited?
Either that or the board is just messed up for me. :hmm:
Wow that is weird. Anyways yeah, this particular 640m has pathetic gddr3 ram attached to it. The bandwidth is pathetic, even for a small chip like gk107.
i can very accurately calculate gk104 gtx 680 by this information on mobile part.
1536 virtual cores act more like 768 real cores divided by 512 gk110=150%
the 1004mhz vs 700mhz balance each other out due to the bandwidth constraints.
150% gf110
+6% give
-6% take
--------------
=gfk104 is anywhere from 111% to +132.65% of a 7970 give or take 28%!!!!!
i would put money on it
![]()
^^ There are two variations that are shipped with the same moniker.
From AT:
555M 'B' spec is the one that Alienware uses in its M14x.
Cooling
One of the tactics used by Nvidia to squeeze maximum performance out of the new Kepler mobile chips is performance scaling. Every laptop has a maximum amount of heat it can cool - so why not make sure all of it is being used?
The answer to that question starts to become evident when playing games on this laptop. While the palmrest remains in the mid-80s, the middle of the keyboard becomes extremely warm, reaching temperatures up to 105 degrees.
That’s nothing compared to center-bottom of the laptop, where we read temperatures of up to 128 degrees after playing Battlefield 3 on Ultra. That’s unacceptably warm - it’s hard to imagine using this laptop on anything besides a desk if you want to engage the GPU.
I asked an Nvidia rep what they were going to do to ensure that the dynamic performance scaling did not result in high external temperatures. The answer I received was that it’s up to the laptop manufacturer as the thermal capacity of the chassis is often determined before they select a GPU. It appears Acer has been very liberal with the maximum temperatures it will tolerate.
What clocks is the GT555m running at? This test
http://www.notebookcheck.com/Test-Alienware-M14x-Notebook.53568.0.html
says 590, the pcper test says 753?
I'm glad most people are impressed with the performance... but if i read the above statement... I'm more scared than impressed..
Look at the device that it's in, though. Although we don't have a full set of images in the article so that we can see if from all angles, if it's like most other ultrabooks, it won't have much for vents or a cooling system and will be cramming a lot into a small area.
It's really no different then complaining about a 7970 running hot if you put an inadequate fan on it and don't provide enough space for case vents and fans. The chips are probably fine, but anything can run hot if the cooling system is poorly designed.
I feel slightly confused, but how did you reply to a post that comes after yours considering that it does not indicate that your post was edited?
Either that or the board is just messed up for me. :hmm:
I think the average performance increase over the GTX580 should be something around 60%.