A long time ago collected I mini-computer. But the thing is 3D modeling and what really must admit – trivial toys has made this box much to think about, and I was nervous. But to just connect the graphics card to it slot PCI-E X4, but there is no place in the housing. And the food can not provide (unless talking about very very budget plugs). Any solutions to this problem available on the market than they did not suit me and that eventually happened, I will try to describe in this article. Ask a cat who’s not afraid of large quantities of pictures!
To connect the graphics card required a PCI-E riser for 4 lines with the extra power with the ability to manage them, if the power supply is separate. So that immediately disappear the normal stub and many are painfully familiar with mining riser card with USB cable as the interface.
Mass products mass quality
But out of that more or less satisfies my queries can be found on the Internet:
- PE4C V4.1 — first Board installed in the slot clearly does not fit in my PC size. Even the HDMI cables are quite rigid, there are still 2! And the price at ~ 140$ I thought is not humane.
- EXP GDC — sushestvovala version for pci-e x4, but had the same inhumane price, 2 already seen an HDMI cable. Even now her image can not be found — very rarely sold outside China. But for pci-e x4 charge more overall than PE4C
The version for M2. For the usual PCI-E is like sank into oblivion
- Raiser from ADT-Link — at the moment my throwing has not been submitted. And now information on them not a lot. But I felt
wildlystrange so much to vary the price of the device from the loop length.
Not finding an appropriate solution had to choose from two options — to score or do it yourself. It is clear that for the first variant, the article could have been on this finish, but I think I will continue.
After meeting in various communities devoted to the topic, it was decided to make riser universal, not only for themselves — and to the laptop (via Mini Pci-E, M2, or even MXM) and the computer in the x16 slot without any limitations only 4 lines of data exchange!
Here is a list of requirements that I set myself:
- Power supply is only 12v. 3.3 v to get the riser card with dc-dc Converter.
- Power management is not dependent on the used type of power supply (managed or ordinary ATX PSU on the 12v)
- Connecting various adapters using the same type of detachable cables (no soldering).
- Split the x16 interface 4 groups. Thus for interface x1-x4 – 1 cable, x8 – 2 cable and 4 cable x16.
- Sometimes I observed the situation, when connected to the laptop graphics card via fed EXP GDC laptop power supply at 19v (connector is the same – it is necessary to stick) were inspired to add the indication of the input voltage within the acceptable range: 12v ±5%.
Wishlist described, courage accumulated enough — it’s time to translate! Riser is essentially an extension cord. And cable is a main part of it. As such it was applied varieties of LVDS cables, the so — called micro coaxial cable assemblies (micro coaxial cable assembly). They are often used to connect the matrices of various display devices.
Naked cable 18+
30 lived and only 2mm in diameter
Although in the open market to find them extremely difficult, I managed to find a manufacturer in China willing to manufacture such cables in any quantity (even 1pcs) any length and with a suitable connector.
When selecting the interface cable was gone, I was finally able to develop the scheme of payment of the riser and the selection of components. In the end system Board has been ordered, components bought and assembled:
The top of the Board
The bottom of the Board
- Power connector 8pin (15A max current), combined with the enable signal (for ATX power supply)
- Diagram display supply voltage within the acceptable range (+12v ±5%) window comparator. Green led – the voltage is normal, red – out of range
- Power management – MOSFET in case of use of power without control and the supply signal PS ON. The control signal serves as a power supply of 3.3 v on the host
- Buck DC\DC for getting 3.3 v
- Connector cooler
- LVDS connectors for interface cables
- PCI-E x16
- Short circuit protection and over voltage – fuse and a TVS diode.
- Connection of additional power supply of graphics card
On the other hand cable plat-slot adapter for target device:
A significant drawback of this solution (as well as its competitors) — it is impossible to quickly connect/disconnect riser without the need to disassemble the laptop/computer. And connectors are not intended for external use and have a low mechanical strength and low resource. Therefore, in addition made that adapter with a more robust connector (the cable with such connectors from to make it is impossible… for reasonable money):
Such connectors are used in docking stations for smartphones, tablets and other devices
Connection with 2 cables, and the data adapter connect them
All components soldered on Board, the cable is connected — it’s time to cross your fingers and test!
In the photo the prototype differs from the final version.
Since connected 2 interface cables — got PCI-E x8.
Through the various tests there were no problems and the card worked stably under load, and the bus frequency is increased (gen3)
For testing I managed to find a laptop with a slot M2 Key M with support for NVME — MSI GE62 6QD. But for the prototype was manufactured adapter with keys M+B for greater versatility, it is therefore possible to use only 2 lines of the 4 available:
Since it was a prototype, the application of tape and removal of dc/dc on a charge is quite pertinent
Запуск ноутбука с EGPU. БП запускается автоматически при включении ноутбука
Due to the presence in the notebook integrated, and discrete graphics card had trouble with installing drivers
Work under load
Unfortunately, these glands were in my possession a very short time and to perform more detailed testing I have not had the opportunity after receiving the final version of the riser. So I had to settle for just this iron:
- MP Asus Q87T
- CPU Core I3 4150T
- RAM 2*4GB Crucial DDR3L SO-DIMM PC-12800
- Wi-Fi / BT module Intel Dual Band Wireless-AC 7260
- SSD mSATA 120GB Crucial M500
- HDD 2.5` Seagate Momentus 500GB
- MSI RX 560 4Gb
For what this was all about really
Of course, the configuration is not productive and gain a significant advantage from a connection on the bus x4 x1 is failed in various tests. Often it was all about low iron.
The difference is within the error
Game type MOBA (WOT, for example) showed indifference to the bus in this configuration when there is sufficient video memory no need to load the data in small enclosed locations.
But in online games with the open world, especially in places of a mass congestion of players, the difference is quite noticeable. Here are 3 measurement FPS in the game Black Desert:
|pci-e gen1 x4 ≈ pci-e gen3 x1|
|pci-e x4 gen3|
Plans and results
Though the project was conceived as a universal and not only for themselves, but not particularly popular find. Not find. Nevertheless, I got what I wanted and invaluable experience and knowledge. According to a negative result — too result!
Also, I’m often asked why I have not tried to implement support for the currently fashionable interface Thunderbolt3. The problem is that this interface will require licensing from Intel. And no documentation for the controllers just will not give. There is even a narrow circle of decision makers on Thunderbolt3 under the patronage of the same Intel. Me of course there was not accepted.
Although there were rumors that this interface will be open and available to all, but at the moment it’s just a rumor and the standard remained closed. But I’d love to try to develop the project in this direction.
Not enough questions were about the connectivity option, instead of MXM graphics cards. Plans for such an option was, but had to abandon it for two reasons — came to an end funds for R&D and I don’t have anything to test it.