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Mobius 1

macrumors 6502
Original poster
Feb 11, 2011
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USEA
so, we know that thunderbolt theoretically can be connected to a ext GPU

the problem is, can i mount a GPU on one of those?

i will be using a 6750 1GB GDDR5 or do i have to use a Mobile version of 6750?


thanks,

13" btw
 
so, we know that thunderbolt theoretically can be connected to a ext GPU

the problem is, can i mount a GPU on one of those?

i will be using a 6750 1GB GDDR5 or do i have to use a Mobile version of 6750?


thanks,

13" btw

It is possible as another poster had mentioned. Just gotta make sure the card fits in the case.
 
see the Echo™ Express here
no word for prices of availability, of course.

And no word on support for GPUs at all. If you look at the product site, it only talks about capture cards, RAID cards and stuff. People think external GPU is simple as getting that thing and then slamming any GPU in it and then it would somehow magically boost your graphics performance. It's far from that.

First off, it needs extensive software support. Your internal display is still connected to the internal GPU(s) (if you have 15/17", then it is connected to the iGPU and dGPU). You will probably need something similar to CrossFire to push the load from the internal GPU to the external. Since Sonnet does not mention anything about this, they probably are not developing it for this purpose. Connecting an external display to the ext GPU might be easier from a software standpoint as USB GPUs have existed for quite awhile (even for Macs). That would eliminate the need for getting the int and ext GPU play along.

Secondly, Macs don't use standard PC GPUs. Macs use EFI which means the GPUs have special firmware in it. This would force you to use the GPUs that Apple offers, unless flashing works for the external GPU as well.

Thirdly, Thunderbolt offers only 10Gb/s while PCIe 2.0 x16 offers up to 64Gb/s. 10Gb/s should be sufficient for some GPUs but higher-end GPUs would most likely take a hit from the limited bandwidth. That might make this whole thing obsolete as 6750M could ens up being faster.

All in all, it's nowhere near as simple as some people make it sound like. That Sonnet box is a good start but you will need more than that.
 
And no word on support for GPUs at all. If you look at the product site, it only talks about capture cards, RAID cards and stuff. People think external GPU is simple as getting that thing and then slamming any GPU in it and then it would somehow magically boost your graphics performance. It's far from that.

First off, it needs extensive software support. Your internal display is still connected to the internal GPU(s) (if you have 15/17", then it is connected to the iGPU and dGPU). You will probably need something similar to CrossFire to push the load from the internal GPU to the external. Since Sonnet does not mention anything about this, they probably are not developing it for this purpose. Connecting an external display to the ext GPU might be easier from a software standpoint as USB GPUs have existed for quite awhile (even for Macs). That would eliminate the need for getting the int and ext GPU play along.

Secondly, Macs don't use standard PC GPUs. Macs use EFI which means the GPUs have special firmware in it. This would force you to use the GPUs that Apple offers, unless flashing works for the external GPU as well.

Thirdly, Thunderbolt offers only 10Gb/s while PCIe 2.0 x16 offers up to 64Gb/s. 10Gb/s should be sufficient for some GPUs but higher-end GPUs would most likely take a hit from the limited bandwidth. That might make this whole thing obsolete as 6750M could ens up being faster.

All in all, it's nowhere near as simple as some people make it sound like. That Sonnet box is a good start but you will need more than that.
As i have previously posted, i dont expect powerful ext GPUs till optic thunderbolt.
 
As i have previously posted, i dont expect powerful ext GPUs till optic thunderbolt.

Even then it may not be enough. Several sites have reported that Thunderbolt 2.0 will deliver 50Gb/s and will be available sometime around 2015. PCIe 3.0 will make its debut in 2012 along with Ivy Bridge. x16 slot will then provide up to 128Gb/s. While it will take time for GPUs to really utilize the extra bandwidth, high-end GPUs may already require way more than 50Gb/s when TB 2.0 hits.

External interfaces have too many features they need to support, that is why they will never achieve the bandwidth of PCIe (well, TB controller is connected to PCIe slot so that is one reason alone).
 
Even then it may not be enough. Several sites have reported that Thunderbolt 2.0 will deliver 50Gb/s and will be available sometime around 2015. PCIe 3.0 will make its debut in 2012 along with Ivy Bridge. x16 slot will then provide up to 128Gb/s. While it will take time for GPUs to really utilize the extra bandwidth, high-end GPUs may already require way more than 50Gb/s when TB 2.0 hits.

External interfaces have too many features they need to support, that is why they will never achieve the bandwidth of PCIe (well, TB controller is connected to PCIe slot so that is one reason alone).

Hadn't read about TB2.0 I personally expect that Thunderbolt 2.0 100Gb/s wich is faster then PCIe 2.0 however as you say by then there will be PCie 3.0
I can see it being possible however, maybe using multiple TB ports?
 
Well, here's the upside. Intel and Apple produced an interface that has native support for PCIE. Then, they endowed it with 10Gbits bandwidth which is quite a lot. So, thats equivalent to a PCEI 2.0 x4 slot which is nothing to sneeze at. The points made earlier about the difficulty of routing an external GPU's output to a laptop's internal display are valid. But, many of us use our MBPs as desktop replacement with external displays. So, there's some hope this can be resolved with some clever engineers and creative licensing. Considering the current state of laptop GPU's even a gimped desktop GPU would be much more powerful than what we've got now.

I'm optimistic that over the next yet we'll start to see some external gpu options pop up.
 
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