ADT-Link R43SF power supply help
Hi guys, Im doing a project where I'm turning an old laptop into a desktop pc.
I am using the ADT-Link R43SF for the graphics card and have got it all working using a ATX psu. I want this pc to be small so I looked into using DELL DA-2 8PIN 12v 220w power supply. This is fine for the gpu 6pin power supply as they are 12v as well but the R43SF adaptor uses a 4 pin floppy connector. The sata to 4pin that came with the adaptor has a yellow and red red wire on it that normally means 12v and 5v. Would it dangerous to use a 12v to 5v convert or is there any other options of power both gpu 12v and the adaptors 5v without using a ATX psu.
Thanks in advance
It only uses 12V from the floppy. Look up PCIe on wikipedia, it shows that a PCIe slot provides 12V and 3.3V. The R43SF has no components to get 3.3V from 5V or 12V, therefore 3.3V must come from the M.2 connection.
Here's an example using a 12V only power supply:
Is there a way to power the 4-pin floppy power cable (berg connector) with the Dell DA-2?
Since the Dell DA-2 only powers 12v and not 5v which is required for the 4-pin berg connector, I'm not sure if this is possible.
@simon_jansen, PCIe uses 3.3V and 12V. The R43SL does not have a voltage regulator so it means that 3.3V is coming from the M.2 slot. 5V is not used anywhere in that case. So all you have to do is connect 12V and ground to the floppy power connector.
Examples of adapters that use 5.5V to make 3.3V:
My situation is that I want to be able to run graphics cards that don't require 6/8pin pcie power cables using the ADT-Link R43SL.
This means the R43SL would need to provide 75w via the pice x16 slot. According to this website ( http://www.playtool.com/pages/psuconnectors/connectors.html#floppy) the maximum amperage a 4-pin floppy connecter can handle through it's 12v rail is 3A. This means that a maximum of 36W can be provided via the 4-pin floppy connecter (assuming you are correct in that the 5v rail in the floppy connector cannot be utilized by the R43SL). According to this website ( https://forums.tomshardware.com/threads/is-there-really-this-much-difference-in-power-consumption-among-nvme-ssds.3079717/) the m.2 spec limits power draw to 7W. This means the R43SL would only be able to provide 43W to a gpu via the x16 slot, which is not enough for non-external-power graphics cards.
I am correct in this assessment that the R43SL is not suitable for gpu's that don't have pcie 6/8-pin power connectors?
@henny, the limit is not the power floppy connector. There's no power delivery negotiation in that connector, so the GPU could try to take more than 3A and the wire might melt if it's not thick enough.
The problem is that the GPU is connected via PCIe x4 -> M.2. A well behaved PCIe device will start with low power and request higher power. The M.2 slot can deny that request.
I think section 6.8, 6.9 of the PCIe base specification (rev 3) explains this. I don't know if you can override the values used by the Slot Power Limit control mechanism (which is something you would want to do since you are providing an alternative power source to the R43SL).
As an alternative, a PCIe switch could be connected. In that case, the downstream slots of the PCIe switch may have a higher power budget than the upstream link. An example would be something like the Netstor NA255A.