PC Processors

[allankg]

I need help for a friend of mine. As soon as I recommended something (the second RX 7700), it became my duty to have an answer for this:

# First scenario
- AsRock RX 7700
- 5700X3D
- B450M PRO-VDH MAX
- Corsair 550W PSU

## Considerations
- All items were chosen without my review
-- Despite all the tips

## Result
- No video
- GPU fans don't even start
- GPU Leds don't even start
- Old GPU works (simple card, yet-another-GT210-rebranding-or-refresh)
- Only a single HDMI out to test
- GPU returned
- PSU returned
- PSU came with a single default PCI-E standard cable, splitted onto 2 6+2pin.
-- Thus, the card relied on a single cable

# Second scenario
- Sapphire Pulse RX 7700
- 5700X3D
- B450M PRO-VDH MAX
- XPG Kyber 750W

## Considerations
- He bought the Sapphire one after me helping him after checking lots of reviews and PCB design.
-- Yup, it was supposed to be good
-- Only ASUS TUF would be a better choice
--- too expensive
- He bought the XPG Kyber after being sold to the marketing
-- I'd have never recommended it

## Result
- No video
- GPU fan turns on
- GPU led turns on
- Old GPU works (simple card, yet-another-GT210-rebranding-or-refresh)
- PSU came with a single default PCI-E standard cable, splitted onto 2 6+2pin.
-- Thus, the card relies on a single cable
- PSU came with 2 PCI-E 5.0 crap cables, with a "600W" label, despite the fact that such low qual
ity PSU would never support both cables at the same time.
-- According to some specialized tests, not even a single would be 100% sure.
-- yes, I find it bad, as we're downgrading in terms of conspumption specs, the solution from nvidia have been just printing a bigger chip regardless of ATX standards.
--- whatever, I already know some of you will disagree, and I just don't want to discuss it. Let's just stick to the main point.

# Already tried
- turning on and letting the 5700X3D compute a **possible** memory training
-- IDK, some chips of 5000 series are haveing a very slow boot time
- Removed CMOS battery
- Updated BIOS/UEFI to the latest
- UEFI boot only
- No HD connected boot
- **Connected the latest PSU and GPU with the old PC**
-- No video, same issue

# So
- What's the chance of 2 RX 7700 being faulty?
-- Different brands.
-- Different PCB designs.
--- At least were supposed to.
- Anything else that you could help me with?
- Incompatibilities with B450M?
- Incompatibilities with the PSU?

To be honest, he is already saying " _no way, I'm sticking with nvidia, amd is b\*\*\*s\*\*t_ ". I wouldn't be surprised if he replaced the CPU as well as the GPU.

WHAT ARE YOU DOING AMD? It should be just "plug and play".

[FunkZ]

For the Radeon RX 7700 XT AMD recommends a 700W power supply with 2x8-pin PCIe power cables and a 54A rating on the 12V rail.

https://www.amd.com/en/products/graphics/desktops/radeon/7000-series/amd-radeon-rx-7700-xt.html

[allankg]

Yup, I was thinking about that too, but wouldn't it be too much for a 230W TDP card?

I mean, 54A * 12V = 648W

Maybe I'm missing something on electronics here (not being sarcastic/ironic).

---

Edit: I've read/studied again, and it seems like that this "rating" word only refers to the most basic and literal meaning of the word, in other words, it just means that the PSU should be capable of delivering that much power from that rail (PCI-E cords).

Based on that, the current PSU he is using is a 750W rated, with a specific rate of 62.5A on the 12V rail, which means that the PSU is (marketed as) capable of delivering 750W on the 12V rail (more than the recommended by AMD). But to all the next readers, this PSU does not have all the build quality necessary for this case, never ever count on that.

Also, I'm also considering that 230W of TDP represents the thermal dissipation and that the power consumption may vary. For this specific Sapphire Pulse model, it is expected that 266W is the TBP.

So, there's no clear excuse for the RX 7700 XT to not run on this PSU, unless there's another thing to consider.

Manufacturers recommend PSUs ratings much beyond its real usage due to :

- never knowing what kind of setup the customer will use (if you consider a small OC, for example, doubling the rate is not enough)

- capacitors getting worn through the years

[FunkZ]

I don't trust Adata for memory much less XPG Kyber 750W power supply.

Especially if it requires adapters to make it work.

[allankg]

Indeed, I mean, for PSU I'm just shocked with the customers' feedbacks and also from some technical analysis. He chose without asking first, I'm gonna see if he can still return it.

About RAM, IDK TBH, I see as good, but I'll take your tip and do more research about it.

I've added some details on the PSU side in the previous comment, but who knows, maybe the PSU is just not delivering what it was supposed to (sad) .

[FunkZ]

Just to be 100% you stated that the 5700X3D has NO problems booting on the B450 board with the original graphics card GT210 correct?

[misterj]

allankg, this is a processor sub forum. I suggest you post in the Graphics sub forum. John.

[allankg]

My bad, I'll repost it.

What I did :

- chose Graphics

- chose Processor to see if it could have 2 flags (maybe something to be done on this side)

- chose Graphics again

Seems like it kept only the second action.

---

Edit : I can't either repost or add another reply as the website is thinking that I'm flooding. Can someone move the topic for me, please?

[misterj]

allankg, I would suggest not worrying. If they complain over there ask them to remove this thread. Thanks, John.

[elstaci]

One of the main reasons why PSU are rated much higher than the actual wattage used is due to Transient voltages spikes from the GPU Card.

Some Transient voltages spikes, even though it is a extremely short burst, is strong enough to shut down a under-powered or low quality  PSU.

for instance a GPU will work fine on a 600 Watt PSU but the GPU might create a Transient voltage spike rated over 700 watts during a brief burst thus overwhelming the PSU. Thus manufacturer recommends a minimum PSU of  750 watts to take into account these GPU transient voltages spikes.

Many low quality (cheap) PSU can't deliver the proper voltages under stress. Like a 750 Watt cheap PSU may not be able to support the same voltage spikes as a high quality PSU under stress or heavy loads.

[allankg · Accepted solution]

https://community.amd.com/t5/graphics-cards/2-different-rx-7700-xt-not-working-different-brands-is-i...