DIY external GPU via expresscard

[apac]

Hi folks. Since I don't see it talked about on AT at all I thought I'd start a thread about eGPUs for notebooks that have an expresscard slot. This idea has been discussed at length on the notebookreview forums, and there is a wealth of information to be found there.

http://forum.notebookreview.com/gaming-software-graphics-cards/418851-diy-egpu-experiences.html

To summarize the info found in that thread, if you own or purchase a notebook that has an ExpressCard slot (looks like http://dpnow.com/images/delkin-expresscard-cf-2.jpg) it's possible to hook up a desktop graphics card to your notebook. Most consumer-grade laptops do not have an ExpressCard, but it is very common on business notebooks, even entry-level. Notebooks with Intel 4500MHD, HD, or HD3000 graphics are most compatible because they can leverage the Nvidia Optimus technology. This includes Sandy Bridge notebooks.

If your notebook does not have an ExpressCard slot there is currently no way to hook up an eGPU. Likewise, if your notebook does not have one of the aforementioned Intel graphics chips it's (at this time) IMO not worth the $$/effort to try an eGPU.

The cost of the eGPU parts is the customer adapter ($65), a PSU, and a desktop GPU. In most cases the total will run about $220-250, perhaps less if you score some really hot deals. That estimate includes the price of a GTX460 graphics card, which users have found to be one of the best eGPU cost-to-performance values. When paired with an entry-level Sandy Bridge notebook it's possible to have the portability of a notebook and the gaming power of a desktop, all in one, and for a very reasonable price.

My laptop + eGPU parts cost roughly $750 (found a Lenovo E420 on sale). I spent an additional $200 on SSD and memory upgrades. The net result is a Core i5 2410, with 8GB memory, 80GB Intel 320 SSD, and weighs about 4.5 lbs. When hooked up to the GTX460 eGPU and an external display I can comfortably play SC2 on Ultra settings.

Oddly enough, the SC2 main menu screen and cutscenes are rather laggy, but the game itself plays very smoothly. Haven't figured out why that is, but it seems specific to SC2, since 3dmark06 and 3dmark Vantage run pretty well.

I will mention that while there is wide community support for this project, it is definitely still a DIY experience. The eGPU is not usually plug-and-play, and it took me a little while to get mine working successfully. I do have to run a special boot program (community supported by people in that thread) to enable the eGPU. Removing the eGPU while running works fine, but hotplugging it back in will often BSOD. In general I just reboot the machine if I'm re-plugging the eGPU. Most other users don't have this issue, but it wouldn't surprise me if every setup has its little quirks. As I mentioned, it's definitely fun and rewarding, but still a DIY project .

Feel free to ask questions. I've read most, if not all of the 500 page thread on NBR, so I have about all the info you might find there.

 

[Rifter]

few questions.

How do you loop video back to the laptop display from the external GPU?

Also how do you power the 460 while on the go? i would think to support that high of a TDP for long you would need a battery the size of a car battery.

 

[apac]

few questions.

How do you loop video back to the laptop display from the external GPU?

The Nvidia mobile drivers handle this auto-magically. To the system the eGPU appears to be a dGPU on a PCIe link, so the drivers handle it like a dGPU. However, keep in mind that the loopback will give you roughly a 30% performance hit compared to an external display, due to the added data on the expresscard link. I get about 15K in 3dmark06 on an external display @1280x1024, and about 11K on the internal @1280x720.

The expresscard is using a PCIe x1 link so the bandwidth becomes the graphics bottleneck for gaming. Optimus helps this significantly - there is some kind of built-in compression algorithm that makes the link operate significantly faster (Nvidia will not share details on this). The more data that needs to go through the expresscard, the lower your performance, hence the performance loss for internal LCD.

Also how do you power the 460 while on the go? i would think to support that high of a TDP for long you would need a battery the size of a car battery.

This as more of a hybrid desktop/notebook solution. The 460 uses an ATX PSU so it must be plugged in to operate.

The way I see it, most people try to buy notebooks that fall into two categories:
1) I want a lightweight and portable notebook for school/travel.
2) I want a high power gaming notebook that can play all sorts of games and weighs 8 lbs. This will spend most of it's life on a desk, but the user did not want a desktop.

This solution fits both of those, which was exactly what I needed. I can "dock" my laptop with the eGPU at home and game a bit. I can also detach the laptop and hop in bed to watch a DVD, or go to a friends house for my fantasy football draft. It would be difficult to bring this on a vacation or business trip and game, though.

 

[ViviTheMage]

I've been contemplating it with my x220, but I am going to wait for the new cable to hit twice as fast as the current speeds. This is probably the best quote i've read on there, for current purchases though.

Your Lenovo X220 have 2nd generation Intel Core processor & ExpressCard 2.0. However due to eGPU cable limitation, for now, the best it can do is x1.1Opt link with eGPU Nvidia graphic card. The ".1Opt" means it's working with 2.5Gb/s link speed. The performance still great. When HWTools/BPlus able to come out with the solution, you'll be able to setup x1.2Opt (5Gb/s link speed) with eGPU Nvidia graphic card.

For eGPU kit, you can get PE4L-EC2C ver1.5 Package. PE4H-EC2C ver2.4 Package is a bit overkill since for now it's not possible to do x2 link with Optimus. Optimus only engaged with x1 link. I like PE4H because the dimension is bigger & can hold graphic card better. And also with extra PCIe interface I can experiment with them.

For desktop graphic card, I think GTX460 or GTX560Ti is a good choice. Both not too expensive too.

 

[gsaldivar]

Wow I did not know this was possible as a DIY project. Thanks!