I have a prebuilt HP PC that has a Ryzen 5 3400 G Mobile with Radeon Vega Graphics. There is a spot on my motherboard where I can install another GPU. However, my PSU is only 180W and I can't upgrade it to a 300W - 400W PSU because there is nowhere for me to put the 20 - 24pin connector because there is not a 20 -24 pin spot anywhere on my motherboard. Are there any low profile GPU's that a 180W PSU can support?
Not if you just want to use a APU processor's Integrated Graphics.
This website gives your the minimum PSU wattage you need to run a PC computer with various AMD & NVidia GPU Cards: http://www.realhardtechx.com/index_archivos/Page362.htm
The smallest GPU Card requires a minimum of 300 Watt PSU.
I would go to HP Support and see if they have an PSU upgrade for your Prebuilt PC.
What is the Make & Model of your HP Computer?
Thanks that helped me locate a HP Forum Thread that mentions the same HP Motherboard Erica2 as the one you have.
Here are the specs to your HP Motherboard: https://support.hp.com/us-en/document/c06418906
It does mention that HP does have an PSU 400 Watt upgrade for your motherboard: https://h30434.www3.hp.com/t5/Desktop-Hardware-and-Upgrade-Questions/HP-Desktop-M01-F0016-Erica-Moth...
Before purchasing that HP PSU I would contact HP to make sure it is compatible with your HP Prebuilt PC and does indeed have the Motherboard Power connector.
Edit: I was unable to find that HP P/N for that PSU so I would ask HP Support which PSU replaced or upgraded that PSU.
My motherboard doesn't have any 6 pin connector slots either. It only has 4 pin and molex connector slots. I'm probably better off either buying a pre built gaming PC that has a 400W or greater PSU or building a gaming PC than having to go through the hassle of sending my PC to HP for upgrades. Upgrading the PSU for this PC just seems impossible.
Try buying a Pre-Built PC from like IBUYPOWER or some other company that doesn't use Propriety hardware like HP or DELL.
I purchased a cheap Pre-built PC for my wife from IBUYPOWER and so far I have upgraded the PSU, RAM, and CPU on it without any issues. It uses a Gigabyte Motherboard in a Mid-Tower computer case.
This website is very popular to Users who wants to buy a Prebuild PC or build their own: https://pcpartpicker.com/?__cf_chl_jschl_tk__=0dbb751dd825dd5ef64fbb7d960b36b908d2bbb8-1621336517-0-...
The above website you can choose the parts you want and they will build it for you or you can purchase all the parts separately and build your own PC.
Why don't you just sell your current system and build a cheap one yourself? Or gut your current system for it's CPU, RAM and storage. Then buy a compatible motherboard, case and PSU and put the original components in that. Cheap and easy path to upgradability.
If you don't feel comfortable or don't know how to pick the right parts I'm sure there are plenty of people here willing to help you out including msyelf.
Swapping the PSU will void the warranty just as much as taking out the CPU I assume. Taking out a CPU is much easier than a PSU, especially with those ultry small systems where the cables are tucked in everywhere.
I just thought of something you can do yourself to see if you can fit in a GPU wihtout changing the PSU.
The PSU can deliver 180W. A GPU without any power connectors (RX550, GTX1650) can draw 75W at maximum from your motherboard. That means that if your system doesn't draw more than 105W you can put in such a low-end GPU no problem.
To measure the power draw you'll have to take into account efficiency of the PSU. Usually this is mentioned on the specification on the side of the PSU. Say the PSU is a bad one and it only has 80% efficiency, that means it's drawing 105/0.8=132W from the wall if it's delivering 105W. If you measure your power usage during a heavy load on the PC (without stress testing the GPU) and you stay below this 132W power limit you are pretty safe to put a 75W GPU in your system. I think the best way to stress test the system is to run a Prime95 torture test.
The Ryzen 3600G uses 45w (CPU Only)
DDR4 uses 1.2 - 1.5w / GB (2133MHz this will be 1.2w) so 9.6w
Mechanical HDD will use ~2.5w while an SSD will use ~0.3w
Then the Chipset will reserve 8w (for Audio, PCIe, USB)
I'd also be careful of USB Devices., such-as WiFi, Mouse, Keyboard... they'll use a couple watts each as well.
It's VERY unusual for a Desktop PC to have a sub-230w PSU., as that's usually the "Minimum" even for a SFF PSU.
In any case though., we account for the "General" System Setup; and you'll be looking at approx. 65 - 75w usage (w/o Graphics) and up to 95w with.
This leaves between 85 - 115w for a Graphics Card.
Now in basic terms any GPU that doesn't require a PCIe Power Connector should be using < 75w... so will work., but keep in mind the PCIe Slot itself is capable of using up to 125w Power; as such this assumption only remains provided the GPU Manufacturer is keeping within the PCIe "Specification" (see: RX 470/480 Controversy)
With this said... strictly speaking a GPU that does use PCIe Power doesn't NEED to be getting that from the same PSU running your System., and a PSU doesn't need to be connected to a System to work.
Still, I'd say you're effectively limited to things like the GTX 1650 or RX 5300... assuming you want something that will have a clear performance advantage over the Vega 11.
With this said... I'd argue that Pre-Built Systems are and always have been a Rip-Off.
Now your CPU, Memory and Storage will be "Off-the-Shelf" (i.e. not Unique to HP PC)... and the case will likely more-or-less be ATX Design (as it's expensive using Custom designs)
This means with a simple switch to an A420 Motherboard (< £50) and 430/500w PSU (< £50) you effectively will be able to use basically ANY GPU on the Market.
People always make the mistake of thinking the "Recommended PSU" is what THEY need., when those figures are assuming you're pairing with a High-End Motherboard, Lots of USB, Lots of HDD and High-Performance CPU. That is to say they're covering their behinds, so people don't go "Hey this won't run on that PSU"
In said cases they're adding ~250w + PSU Peak usage + 30% (as under 70% Utilisation is the most efficient power delivery)
I mean my R9 360 recommended a 450w PSU (120w GPU) and my RX 480 recommended a 550w PSU (145w GPU)
Then there is my current RX 5700 XT... claims it needs a 700w PSU., I'm running it on a 430w and I'm Overclocking with an Extended Power Limit of 50%.
As noted., the PSU Recommendations are frankly over estimations by a big margin for MOST people's systems.
Instead consider what you're actually running; rather than a HEDT CPU that'll want to use 125 - 180w on it's own.
Like, if I were running a Threadripper; sure I'd want a 700w PSU... but on my R5 1600 (which is still "Mid-Range" in terms of performance)., yeah don't need anything close to that much power.
So, just consider such things.
A quick Motherboard and Power Supply swap will mean you'll be good to get a decent GPU.