Crossfire issues? Settings problem? Odd 2x AMD RX570 with 4GB RAM performance.
Crossfire issues? Settings problem? Odd 2x AMD RX570 with 4GB RAM performance.
Hello! I've been attempting to resolve this problem and have reached a point where I need to dig deeper into the details. Before you proceed, I'd like to politely request that no suggestions like "upgrade your entire system" or "switch processor generations" be used — it's not an option. Despite the ongoing challenges in today’s world (inflation, component shortages, etc.), I live in an area where hardware is very costly. I might just manage to get some RAM sticks if that’s the case, but that seems unlikely. Even a CPU upgrade to a low-end model (plus cooling) probably won’t work for me right now. Some background info and my current specs are included along with its evolution. Not long ago, my setup looked like this:
- MSI Z87-G43 Gaming
- Core i7 4790 (non-K) CPU
- WD Blue NVMe SSD via PCI-Express x1 adapter
- Samsung 870 EVO 1TB SATA SSD
- 24GB DDR3 1600MHz (2x 4GB 2400MHz 1.65v + 2x 8GB 1600MHz 1.35v) sticks
- Sapphire AMD Radeon HD7950 3GB GDDR5 GPU
- BeQuiet DarkPower Pro 550W PSU
- Two DELL U2311H 23" 1920x1080 IPS panels (vertical pivot/portrait)
- One DELL U3011 30" 2560x1600 IPS panel (landscape)
This machine is mostly used for work under Linux, but I also run a multiboot with Windows 10 64bit for single-player games or GTA5 Online. A close friend, recognizing my struggles at native resolution, offered me two AMD Radeon RX570 GPUs and a Corsair RM850 PSU. I tried them out — initially everything worked smoothly, achieving stable 60 FPS in GTA5 Online at native settings. However, the GPU temperatures rose significantly (around 72–74°C) and fans kicked up loudly. After some research, I discovered my motherboard only had one PCI-Express 16x slot with full Gen 3 bandwidth, while the other was limited to Gen 2. This, combined with overheating concerns, made me reconsider.
I found a friend with a compatible motherboard and agreed to swap. The new setup included:
- MSI Z97 Gaming 5 (Z97 chipset, three PCI-Express 16x Gen 3 slots + wired to CPU at Gen 2)
- A motherboard with four PCI-Express 16x slots (Gen 3), plus a M.2 slot
- Removal of the x1 NVMe adapter and direct connection of WD Blue SSD
Despite these changes, performance dropped sharply in GTA5 Online — from around 45 FPS to 40–48 FPS, especially when driving through busy areas. Even with overclocking attempts (BCLK, ring ratio), the issue persisted. I also noticed that under certain conditions (like playing in grassy environments), the GPU temperatures spiked but didn’t exceed 81°C.
Further investigation revealed that my GPU usage patterns changed unpredictably — sometimes high, sometimes low — and the system struggled to maintain consistent performance. I tried various fixes: reinstalling Windows, updating drivers, adjusting graphics settings, and even disabling microcode patches. However, none resolved the core problem.
Now I’m at a crossroads. How do I accurately pinpoint the issue? I'm feeling quite lost.
You should verify if the motherboard is compatible with Crossfire. While it works with Intel chips, the hardware must support it. Besides that, 1600 MHz RAM is probably limiting your performance now. A higher amount would be better these days. The temperature range of 77-81°C is quite high. My RTX3060ti hasn't exceeded 69°C even under heavy use. The FPS drop hints at vertical sync or another stabilization feature being enabled, which restricts the frame rate (V sync helps on screens capped at 60Hz). I learned about this V sync after investing heavily in a custom build (5900X / RTX3060ti / 32GB, etc.), only to reduce performance with a 55-inch display that runs at 60Hz. Until a better display is available, I won't fully realize the potential of my system.
Hey, thanks for responding! 1) Yep, the MSI Z97 Gaming 5 is both CrossFire and SLI certified. The previous one - Z87-G43 Gaming - was just CrossFire with no SLI certification. 2) Heat output in Furmark is probably expected to be crazy; though that is the least of my concern now (to be optimized when there's a need for it). I rather used it as a point of reference justifying that the GPUs truly do something/ramp up to their specs. 3) My monitor is exactly the 60Hz case here so it does use V-sync not to get the "tearing" effect. The problem starts when it drops *below* 60 FPS (60Hz) down to mid-40's range...
Your RAM speed, BTW, could be inducing up to 20% bottleneck, more if the mismatch is a factor (and it could be). I see similar FPS drop with an RTX3060ti and a 5900X even running DDR4-3200 because of vertical synchronization. At 3840x2160 I see as little as 28-42 FPS, especially with OBS recording. So I would say the RAM speed is an issue but the 60hz is your biggest problem. With 60hz displays, video upgrades are pointless -- a bitter lesson I've learned the hard way. Unfortunately, my situation doesn't allow me to upgrade the display for awhile yet. Edited April 20, 2022 by An0maly_76 Revised, more info
Thanks again. I will give it a shot and pull the trigger on a 2x8GB Kingston HyperX Beast 2400MHz set to replace the Samsungs and put my entire memory lane on XMP. I'll see where it leads me. I found an offer online that's within my budgets. For 60Hz displays - well... I'm trying to reach the stable 60 FPS mark, not go above it - and that's already an obstacle here I cannot surpass. (Previous GPU was not only running below native resolution for this screen, but also keeping it at about 45-ish range all the time)
Additionally, another point popped into my head (still pending the RAM package). It seems this question has been asked several times, but... does CrossFire double the VRAM? GTA5 "seems to agree," letting me use up to 8GB for graphics while running 2x4GB cards. Could that be the limiting factor at the end?
Consider the specs you're working with. You're using DDR3 RAM, not the newer DDR4. That setup operates at a lower speed and has higher latency. The DDR3-1600 should work just fine. It wouldn't be worth spending over $200 on an outdated kit for obsolete hardware—frequency changes will have only a minor impact. If you locate used or new models like DDR3-1866 or DDR3-2133, that's ideal. Also keep in mind: DDR3-2400 is quite demanding; your i7-4790 might struggle with it, especially at high frequencies. While DDR3-1600 and DDR3-2133 usually perform best, the XMP settings can be tricky. The i7-4790 may not handle the full speed unless configured properly. The MSi Z97 Gaming 5 board supports several PCI-E slots, but the i7-4790 only has three X16 lanes. You’ll need to balance configurations—think x8 + x8 + x0 for your two RX-570 graphics cards.
A few things to verify: Check which BIOS version is installed on the board. The latest available for that model is version 1.D from February 2016. Make sure you’re using the first two X16 slots and set the board to run at x8 + x8 + x0.
When adjusting in-game graphics, some games can auto-detect your hardware and pick settings based on what they think is best. You might see changes like High, Medium, or Low depending on your previous setup.
Lastly, keep in mind that older CPUs with Spectra/Metldown patches often saw a performance drop. If you’ve already applied those updates before swapping the board, you should still see similar results. VRAM usage is separate from SLI or Crossfire—each GPU gets its own memory. In your case, you have 4GB of VRAM in Crossfire, not 8GB. Exceeding this limit can cause lag because the system starts using extra RAM for data overflow. With your old board, the X16 slot was running at PCI-E 4.0, which limited bandwidth and hurt performance. Switching to PCI-E 3.0 removed that bottleneck, letting GPUs run more efficiently—though it also raised temperatures slightly. You might want to tweak fan curves in MSi Afterburner or AMD software to prevent throttling. If you need higher temps, consider raising the threshold a bit before the system starts limiting performance.
Hey there! Thanks a ton for the thorough and clear response! Really appreciated it. I’ve located two 8GB Kingston HyperX Beast 2400MHz CL11 units, which should line up perfectly with my current 2x 4GB (identical specs). I’ll swap in the Samsung options.
I found a bundle for just $73, including shipping, so I’m going to go ahead and place the order. I’m hoping this will help bridge the gap between DDR3 and DDR3L, and maybe push the memory bus up a notch. From what I saw on my existing Kingston drives, they support two XMP profiles – 2133MHz and 2400MHz. Thanks for the heads-up.
In the worst scenario, I’ll stick to 2133MHz XMP or try tweaking everything to hit around 1866MHz as you suggested. Still, there’s a good chance we can get full performance. The board specs say it should work, and my CPU is top-tier (the “K” designation is clearly the best). I’m limited mostly by the CPU’s lane count, so I’m considering running at x8 + x8 + 0. I was wondering if the M.2 slot itself could be a bottleneck; if not, it should perform well.
I checked my specs and the BIOS matches what you said. MSI’s site also confirmed similar settings. My auto-detection seems to default to high speeds unless more VRAM is needed – which would be the case for complex scenes. I’m guessing the chipset will handle it, but I’ll keep an eye on the numbers.
My BIOS is exactly what you mentioned; I double-checked with MSI’s site too. It looks like I might have slightly higher auto-settings than usual – it works fine unless I need more VRAM (like for detailed textures). I’m pretty sure it will run smoothly, but I’ll monitor closely.
Regarding Meltdown and Spectre, my old Windows probably didn’t get the latest patches. I blocked updates before this happened. I work mostly on Linux now – dual-boot only for gaming – so security isn’t a huge concern. Plus, it’s heavily protected by another Linux system acting as a firewall, NAT, DNS, etc.
Thanks for the tips! I’ll keep an eye on temperatures and fan health. If the GPU heat becomes an issue, I’ll have to do some tweaks later. For now, it seems like this setup could be solid – just watch out for VRAM limits first.
Keep up the great advice, Rascal!