MP 1,1-5,1 Questions on powering a Vega 64/56 on a flashed 4,1

[wewishyouhealth]

So, some months ago I have bought a 4,1 very cheaply (I am addicted to them), and recently, I got the idea of using a Vega card in it - now, it just so happens that I was given a Vega 64 by a "friend", and while it’s a very pleasant idea - it requires Pixlas. And I am very uncomfortable with it, as much as I would like to use that Vega 64 somewhere at all, it looks very messy.

Now, I still need a GPU for it, and a Vega 56 is close enough, plus I read it doesn’t necessarily need Pixlas - but all of the opinions I have found and read are very diverse - in the end, I haven’t found anything conclusive enough to tell me if it’s safe/stable enough without Pixlas.

Can I run then a Vega 56 without any modifications, just through the standard 6-pin connectors?

Lastly, I would still highly prefer to use my 64, and so - what is the easiest, least complex way to do Pixlas? I have very unstable hands, it’s a nervous condition, and I dislike working on cables.

 

[tsialex]

Can I run then a Vega 56 without any modifications, just through the standard 6-pin connectors?

If you want emergency shutdowns every time you run it full throttle…

Lastly, I would still highly prefer to use my 64, and so - what is the easiest, least complex way to do Pixlas? I have very unstable hands, it’s a nervous condition, and I dislike working on cables.

There is a thread for this exact topic:

Pixlas 4.1 Mac Pro mod

I'm creating a thread for my 4.1-->5.1 mod to keep everything in one place. I will document my upgrade to X5690, PCIe SSD (Apple SSUBX) and PSU mod to allow for two modern gfx cards using only the internal PSU. I have gotten my Mac Pro now (2x 2.26GHz) 4.1 from 2009. It had one Nvidia 120GT...

forums.macrumors.com

 

[wewishyouhealth]

If you want emergency shutdowns every time you run it full throttle…

How come there are so many threads and posts of people saying it’s "within limits" then?

Thank you kindly for the link - I would have to try and work it out outside of the case though, I don’t have good enough lighting to work in it, and too little space.

 

[tsialex]

How come there are so many threads and posts of people saying it’s "within limits" then?

People says that "works" because most never ever use the card full throttle.

The AMD reference Vega 56, the one with the blower type fan heatsink combo, is a 210W TDP card without PowerPlay and if your Mac Pro have a good tolerance, would work for light/medium usage.

The problem is that any gaming cards will draw considerably more power, Tom's Hardware measured almost 325W from the Vega 56 they tested.

Since Mac Pro can safely provide ~180W (90W from each mini-PCIe connector) continuously from the two mini-PCIe power connectors, the math simply doesn't work. First time something triggers the PowerPlay full power draw, you have a SMC emergency shutdown. Even a Sapphire Pulse RX 580 can cause a MacPro5,1 SMC emergency shutdown when used full throttle.

Btw, the 75W from the slot and 75W from each mini-PCIe 6-pin is a little lie that people use to justify the bad choice. No GPU made after the reference AMD "melting PCIe slots fiasco" RX 480 ever used over 45W from the PCIe slot, most use around 30W.

Buy the cable and make a Pixla's mod.

 

[reader50]

Lastly, I would still highly prefer to use my 64, and so - what is the easiest, least complex way to do Pixlas? I have very unstable hands, it’s a nervous condition, and I dislike working on cables.

Are you friends with any local nerds? Someone you would trust to do the Pixlas mod for you?

I've done Pixlas on my 4,1 and it is finicky. Also, shaking hands would be a real problem. So maybe a deserving young neighbor could earn a few Jacksons, and solve your problem?

 

[keksikuningas]

Are you friends with any local nerds? Someone you would trust to do the Pixlas mod for you?

I've done Pixlas on my 4,1 and it is finicky. Also, shaking hands would be a real problem. So maybe a deserving young neighbor could earn a few Jacksons, and solve your problem?

alternatively, if it's an option, OP can use a normal PC PSU externally just for the GPU. Is it as simple as it sounds? I never tried it

 

[wewishyouhealth]

Are you friends with any local nerds? Someone you would trust to do the Pixlas mod for you?

There is my boyfriend - but he lives 300 km away, and I won’t see him for a couple of months for sure. He has a photo lab as a fun fact. Maybe I could ask my mother’s partner to help, but I don’t know how well he will approach the idea of it.

I’ve done Pixlas on my 4,1 and it is finicky. Also, shaking hands would be a real problem. So maybe a deserving young neighbor could earn a few Jacksons, and solve your problem?

The part I am the most scared of is all the cutting, and I guess insulation removal, though I could just get a tool for that. Also that tape - I know it disintegrates when you pull it apart from TheHouseOfMoth’s video.

One good thing is that I could just get a spare PSU to do it on, also I saw a PSU with the clips done on eBay - Maybe that’s an option? It’s 80 EUR

I don’t have that good neighbours in that context, unfortunately. There may be one, but I doubt he would do it.

 

[wewishyouhealth]

alternatively, if it's an option, OP can use a normal PC PSU externally just for the GPU. Is it as simple as it sounds? I never tried it

Could be, but is that large power connector a standard? I don’t know much of PC PSUs. I would have to find one small enough to not hit the rounded upper right edge, and mount it in some way.

 

[keksikuningas]

Could be, but is that large power connector a standard? I don’t know much of PC PSUs. I would have to find one small enough to not hit the rounded upper right edge, and mount it in some way.

I saw people on reddit mount PSUs in the disk drive compartment, could be an option

 

[krakman]

I have been using Vega 56 reference cards in several of my Mac Pros for years without problem.

I do not play games, my work involves video editing in FCPX and Photo editing in Adobe Lightroom.

I have used OCLP to install Sequoia and the system works well.

I've never had a hard shutdown.

My method is to use a reference Vega 56 ( I prefer Sapphire brand) these cards have a low power mode bios switch on the side of the card. I don't remember the exact spec of low power mode but I recall it is within tolerance. It's something like 90% performance with 20% less power.

Do not buy the Vega Nitro cards or the Vega 64, they draw too much power and you will have to do the Pixlas mod.

Buy an EVGA Powerlink from Amazon and two mini 6pin to 6 pin power cables. The power link fits onto the Vega card and smooths out the power draw from the 6 pin cables.

There are many posts on the forum about fitting this card in a Mac Pro, the topic has been discussed many times in the past. A quick search of the forum will help you.


Edit: some power specs that I found on another forum.....


(Vega56, Sapphire reference blower)
Factory stock settings (the baseline):
BIOS1, default 'Balanced' profile - 800MHz HBM2/Auto voltage/Auto clock/Auto temps
Performance = 72.9fps = 100%
Avg. clock = 1387MHz = 100%
Avg. fan = 2315RPM = 100%
Avg. Watts = 175W = 100%
Avg. VDDC = 952mv = 100%

AMD's idea of an efficient BIOS profile:
BIOS2, 'Power Save' profile - 800MHz HBM2/Auto voltage/Auto clock/Auto temps
Performance = 69.9fps = 96%
Avg. clock = 1278MHz = 92%
Avg. fan = 1885RPM = 81%
Avg. Watts = 135W = 77%
Avg. VDDC = 900mv = 95%

Note - this is average not maximum Watts.

 

[wewishyouhealth]

Thank you, I will definitely look into it as well.

 

[SDAVE]

Why don't you get a 6800XT or something? Much better than a Vega and should work out of the box. 6900XT is the max you can get for macOS

 

[reader50]

Why don't you get a 6800XT or something? Much better than a Vega and should work out of the box. 6900XT is the max you can get for macOS

RX 6800XT has a listed power draw of 300W, same as the RX 6900XT. Both would require Pixlas or external power supply. Even the RX 6800 (non-XT) lists a power draw of 250W, which is likely still too high.

Perhaps you're thinking of the RX 6600 (132W) or RX 6600XT (160W)?

Source: Wikipedia RX 6000 specs table

 

[SDAVE]

RX 6800XT has a listed power draw of 300W, same as the RX 6900XT. Both would require Pixlas or external power supply. Even the RX 6800 (non-XT) lists a power draw of 250W, which is likely still too high.

Perhaps you're thinking of the RX 6600 (132W) or RX 6600XT (160W)?

Source: Wikipedia RX 6600 specs table

Yeah probably 6600XT it will be better than Vega which is a heater (I used to own Vega 64) but you still have to flash the ROM afaik

If you can't get your hands on a PC you might be able to buy a pre-flashed 6600XT

 

[wewishyouhealth]

Yeah probably 6600XT it will be better than Vega which is a heater (I used to own Vega 64) but you still have to flash the ROM afaik

If you can't get your hands on a PC you might be able to buy a pre-flashed 6600XT

Well, mainly because of Mojave compatibillity, 6600 XT has a minimum of Monterey, so for me, I would only use it in Sequoia. Also, I not only don’t have any PC, but pre-flashed cards are somewhat expensive, and very rare where I live. An HD 7950 can cost 250+ USD for me, while the same GPU without Apple EFI and bought locally would be just 30 USD. Edit: I just checked, and it’s the postage that produces costs mostly - I have to pay 100 USD additionally for the 6600 you have sent me, and very likely some additional taxes because of Trump.

 

[tsialex]

NAVI cards only work up to Monterey with a MacPro5,1 - no Ventura, Sonoma, Sequoia or Tahoe.