Question RTX 2070 on a PCI 2.0 slot

[gabrielmury]

Hi, I'm new to the forum and I've just acquired a RTX 2070. Here are my specs:

Asrock B450m Pro4
AMD Ryzen 5 2600
8GB DDR4 2400MHZ
Gigabyte RTX 2070 Windforce

I've noticed the GPU was underperforming so I decided to check it out and I've noticed that it has been installed on the PCIE 2.0 slot instead of the PCIe 3.0. Can this be the cause of the underwhelming performance or am I experiencing some CPU bottleneck?

 

[rgd1101]

put it in the 3.0 slot

 

[Dark Lord of Tech]

It belongs in the PCIE 3.0 slot just below the CPU.

 

[gabrielmury]

I will do it, I was just wondering if that will impact the performance?

 

[Dark Lord of Tech]

Impact of PCI-E Speed on Gaming Performance

Many hardware sites have shown in the past that video cards do not show any performance decrease by running in x8 mode and cannot utilize the larger bandwidth provided by the latest Gen3 specification. However, video cards are getting faster and faster so we felt it this is still true. Also...

www.pugetsystems.com

 

[gabrielmury]

Impact of PCI-E Speed on Gaming Performance

Many hardware sites have shown in the past that video cards do not show any performance decrease by running in x8 mode and cannot utilize the larger bandwidth provided by the latest Gen3 specification. However, video cards are getting faster and faster so we felt it this is still true. Also...

www.pugetsystems.com

Thank you very much!

 

[Dark Lord of Tech]

Glad to help!

 

[TJ Hooker]

If that slot had full x16 bandwidth there wouldn't be a big difference between 2.0 and 3.0. But that slot is only x4.

 

[cryoburner]

If that slot had full x16 bandwidth there wouldn't be a big difference between 2.0 and 3.0. But that slot is only x4.

If this is their motherboard, then it appears to be 2.0 x16 for that second slot. It does appear to operate as x4 when in PCIe 3.0 mode though, which would offer similar bandwidth to 2.0 x8...

https://www.asrock.com/mb/AMD/B450M Pro4/index.asp#Specification

Techpowerup recently did some PCIe scaling benchmarks that showed the 2080 Ti taking an average performance hit of about 9% at 1080p, 8% at 1440p, and 6% at 4K when running at PCIe 3.0 x4. However, that's a faster card than a 2070...

https://www.techpowerup.com/reviews/NVIDIA/GeForce_RTX_2080_Ti_PCI-Express_Scaling/6.html

The 2070 performs closer to a GTX 1080, and looking at their similar scaling test of that card from a couple years back, we see much less of an average performance hit. 4% at 1080p and 1440p, and only 3% at 4K. They did also test that card on a 3.0 x4 slot provided by the chipset and saw a greater performance impact, though it was still slightly less of a difference than what they saw from the 2080 Ti at x4...

https://www.techpowerup.com/reviews/NVIDIA/GeForce_GTX_1080_PCI_Express_Scaling/24.html

But yeah, that card should be in the top x16 slot if you want to get the most performance out of it.

 

[TJ Hooker]

If this is their motherboard, then it appears to be 2.0 x16 for that second slot. It does appear to operate as x4 when in PCIe 3.0 mode though, which would offer similar bandwidth to 2.0 x8...

You're reading it incorrectly, when it says "(PCIE3 x4 mode)" for the 2nd slot, it's not referring to operating in PCIe 3.0, but rather that slot is called "PCIE3" and they're saying it operates at x4. And it's only PCIe 2.0. It's not possible for the 2nd slot to be PCIe 2.0 x16 electrically, based on the PCIe lanes available from the CPU and chipset.

 

[gabrielmury]

Guys, thanks for all your replies.

Well, I installed the GPU on the appropriate slot but my FPS are still inconsistent. So i ran a benchmark on userbenchmark.com. Here are the results. There seems to be something wrong with the RAM? It also says my CPU is performing way below expectations. What could be the reason?

UserBenchmarks: Game 101%, Desk 61%, Work 60%
CPU: AMD Ryzen 5 2600 - 82%
GPU: Nvidia GeForce RTX 2070 - 130.4%
HDD: Seagate Barracuda 7200.14 1TB - 81.6%
RAM: Unknown? CMK8GX4M1A2400C14 1x8GB - 38.2%
MBD: Asrock B450M Pro4

 

[cryoburner]

You're reading it incorrectly, when it says "(PCIE3 x4 mode)" for the 2nd slot, it's not referring to operating in PCIe 3.0, but rather that slot is called "PCIE3" and they're saying it operates at x4.

Ah, yeah, that would explain why that specification seemed so weird. : P In any case, they tested PCIe 2.0 x4 in those articles as well, where the limited bandwidth does make a more notable difference.

UserBenchmarks: Game 101%, Desk 61%, Work 60%
CPU: AMD Ryzen 5 2600 - 82%
GPU: Nvidia GeForce RTX 2070 - 130.4%
HDD: Seagate Barracuda 7200.14 1TB - 81.6%
RAM: Unknown? CMK8GX4M1A2400C14 1x8GB - 38.2%
MBD: Asrock B450M Pro4

It helps if you post a link to the results page, rather than just the numbers here. I found it in the list of recent results though...

https://www.userbenchmark.com/UserRun/16032580

And I can see what's likely the problem. You are running a single stick of RAM at a low 2133MHz clock speed, while Ryzen runs best with faster RAM running in dual channel mode (with a matched pair of sticks in the proper slots). This is bound to hurt performance in games that are more demanding on the CPU, and if you are running that 2070 at a lower resolution like 1080p, then that will likely be limiting performance in most games.

Of course, even with the RAM running at a higher speed, it would still be operating in single-channel mode, which reduces its performance. It would be best to use two identical sticks, preferably sold in a matched set, either 2x4GB or 2x8GB.

Ideally, you should be running a dual channel kit of faster RAM in a Ryzen system, preferably at least DDR4-2933, which is the officially supported RAM speed for the Ryzen 2000 series, though 3000-3200 speed can potentially provide slightly more performance. One stick of RAM running at 2133MHz is going to hurt performance though.

As to why your RAM is apparently running at lower than its officially rated 2400 clock speed, that faster speed was likely not automatically detected by the motherboard, so it reverted to 2133. You should be able to manually adjust that setting in the motherboard's BIOS menu though, and set it to 2400, and I believe that RAM might be relatively friendly to overclocking, so you could try setting it to higher speeds as well, such as 2666 or 2933, but you would want to test the RAM for stability at those higher clocks using something like Memtest.

Of course, it would still be operating in single-channel mode, which will reduce its performance. Ideally, you would want a matched set of identical sticks of RAM running in dual-channel mode, either 2x4GB or 2x8GB.

 

[bignastyid]

Single channel DDR4 2400 is what is hurting your CPUs performance. With Ryzen you want atleast DDR4 2933(although DDR4 3000 is usually cheaper) in dual channel.

 

[Seregil Landry]

Somehow this didn't post. But yes, just like bignastyid and cryoburner said.

You are running just one 8 GB stick of Corsair RAM at 2400 MHz. That's going to be a problem. That is just a benchmark, but Ryzen performance relies heavily on faster RAM in Dual Channel mode. Since you are running a higher end GPU, the difference is going to become even more noticable. Here's a fairly good article on that and the infinity fabric:
https://www.tomshardware.com/reviews/amd-ryzen-5-1600x-cpu-review,5014-2.html

I'd recommend using at least 2x4 GBsticks of RAM or the prefered 2x8 GB. You will see a significant improvement.

 

[gabrielmury]

Thank you for your replies.

I've purchased a couple of 8gb DDR4-3200mhz memory sticks (should arrive in a few days). I'll run a new benchmark, then.

 

[gabrielmury]

Ok guys, after some issues with the post office, my sticks of RAM arrived and boy, did they make a difference. I noticed a 20FPS increase on average on Metro Exodus, for example. I also changed the Windows power management which seemed to be holding my GPU back a little.

Here's my new benchmark results (I also overclocked my Ryzen. It's running at 4ghz with a 1.35 voltage): https://www.userbenchmark.com/UserRun/16548610

Thank you guys so much for your help.

Just one quick question: I know my motherboard does not support quadcore. But if in the future I decide to add another couple of identical 8GB RAM sticks will the original 2 continue to run in dual channel?

 

[cryoburner]

Yeah, that looks like quite an improvement. Adding more RAM in the future should be possible. Compatibility issues could potentially occur with RAM purchased separately, but running two pairs generally shouldn't omit you from running the RAM in dual channel mode. You might potentially need to lower RAM speed a little to get four sticks running stable, but not anywhere near the level it was running at before, so any performance hit would likely be minimal.

I wouldn't consider adding more RAM until you actually have need for it though. A number of games have started to benefit from having access to more than 8GB, but I suspect it will probably be a few years before games really start benefiting from having more than 16GB, at least for anyone not multitasking while gaming.