Last updated: March 4th, 2021
After a quick conversation with my friend Simon from Sim Dynamics, I realized I’d made a mistake when I upgraded my 1060 GTX to an EVGA NIVIDIA rtx 2080 ti graphics card. I’d left in an older, lower powered PSU that was probably limiting the available power to my graphics card.
Instead of (correctly) powering the card with separate PCI-E 8 pin connectors, I’d also relied on a single rail and daisy chained the remaining 8 pin connection. Coupled with an underpowered PSU, this was very likely compounding the issue.
As I learned, this is commonly regarded as a mistake and something NVIDIA advise against in their own manual:
What size of power supply does a modern GPU need?
Depending on where you look, modern GPUs are reported to need as much as 360w (rtx 3080). The NVIDIA 2080 rtx ti typically consumes around 280w in a gaming scenario though under “torture” could peak at 350 watts:
When you factor in the 100w or so for the CPU alone, then the HDD’s, lights, fans and so on, there really wouldn’t be much wiggle room left by my previous 500w PSU for big peak demands.
So I ordered a more powerful, EVGA 700 GD power supply which would probably be the safe minimum for my set up.
The unit’s specs certainly seemed good enough for the next few years in my ATX case, and given a PSU installation might make for an interesting read, why not!
How to install a new PSU
There’s a moment in voluntary PC projects where you look and think, do I really need to do this? From the outset my view is that I suspect this is an item that will deliver a marginal gain, if any. It’s difficult to replace something that you’re not entirely sure is going to add any benefit. Nevertheless, we begin at the start.
Begin by cutting all the little tie wraps that hold your CPU and ATX motherboard supply cables. I must admit the cable arrangement in the back of my case was damn near perfect until this moment:
Next, unscrew the PSU from the ATX case:
I loosened the PSU quite early, mostly as a visual aid (some of the cables were tucked behind it). Just be careful when you’re re-orienting the case to work from the front and it shouldn’t be a problem.
Identify the route that the VGA, CPU power and the ATX power cables take – they’ll both plug into the front of the motherboard via holes from front to back of the ATX case.
Removing the CPU power cable was a little tricky, only in that I needed to remove the CPU cooler from the top of the case. Helpfully the CPU cooler covers the top of the DDR4 memory slots too, so it needs removing for more or less any upgrades!
Finally, identify the SATA power cable and carefully remove. There will be a cable for your HDD and SDD (if you have one), and an adapter for the Motherboard.
I thought it best to remove the hard disk so as not to put too much force on the sockets when removing cables. Fortunately I discovered that the HDD had never been screwed into its caddy tray. A loose HD is a bad idea, so I fixed that when it was returned to its position!
Once all the cables are removed, put your new PSU into its approximate position, carefully feed and arrange the ATX, VGA and SATA cables before fitting the PSU into the case.
Once everything is connected, use some tie wraps to organize the cables. That’s it!
Was there a performance improvement?
To test the GPU running with its new PSU, I ran the 3Dmark benchmark. Remarkably, the updated machine scored slightly higher in the test. There was definitely a marginal improvement from running the 2080 rtx ti on two separate 8 pin PCI-E cables. Or perhaps it was that there was more ceiling for power consumption. Or both:
Here’s the results from 3DMARK‘s Time Spy test before installing the new PSU and after:
Before
And after:
What on earth is the difference then?
The difference is quite marginal in the data. Something I did observe while watching the tests run is that after powering the RTX correctly, it seemed the card wasn’t stuttering and dropping frames here and there. Everything seemed an awful lot smoother. This is entirely subjective, though. Do your own tests!
The real world (measurable) benefit? About 1 fps in these tests.
Still, I’m glad I did the work, I learned a lot and the conclusion is fair enough, power your GPU properly!
What PSUs are recommended for my graphics card?
With selecting the right PSU for your PC, there seems to be a minimum to ideal range. For example:
- NVIDIA RTX 3090: PSU minimum 800W. We recommend: 950W.
- NVIDIA RTX 3080: PSU minimum 700W. We recommend: 850W.
- NVIDIA RTX 3070: PSU minimum 700W. We recommend: 850W.
- NVIDIA RTX 2080 Ti: PSU minimum 650W. We recommend: 800W.
- NVIDIA RTX 2080 Super: PSU minimum 650W. We recommend: 800W.
- NVIDIA RTX 2080: PSU minimum 650W. We recommend: 800W.
- NVIDIA RTX 2070 Super: PSU minimum 650W. We recommend: 800W.
- NVIDIA RTX 2070: PSU minimum 550W. We recommend: 700W.
For what it’s worth, my machine is running comfortably with a very good 700w PSU. But if you’re upgrading to the NVIDIA rtx 3080 or 3090, you definitely need to go for an 850 watt power supply or higher.
What are the best PSUs to run a NVIDIA 3080 or 3090 rtx?
If you’re building a new PC or upgrading the PSU in your existing gaming machine, here are a selection of the best power supplies for your brand new and very power hungry rtx 3080 and 3090 graphics cards:
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