CPU_VS_GPU / 2026-09-11
Intel Core i7-8700KvsAMD RX 6900 XT
Complete bottleneck analysis at 1080p, 1440p, Ultrawide (UWQHD/SUWQHD), and 4K with estimated FPS for popular games.
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PERFECTLY BALANCED BUILD
Your CPU (Core i7-8700K) and GPU (RX 6900 XT) are an exceptionally balanced match for gaming at 2560x1440. No realistic component swap would meaningfully improve this build.
Load estimated by the model, not measured on your PC.
- PROCESSORIntel Core i7-8700K
- GRAPHICSAMD RX 6900 XT
- MEMORY16GB DDR4/DDR5
- RESOLUTION2560x1440
Average across the demanding titles at 2560x1440.
Average across the competitive titles, where the processor leads.
What the build draws (545 W) plus headroom.
DEEP-DIVE ANALYSIS
GENERATED BY THE ENGINEThis page breaks down, number by number, what happens when you run an Intel Core i7-8700K alongside an AMD RX 6900 XT. The processor scores 54/100 and the graphics card 40/100 in our model — the interesting part is how they split the workload at each resolution.
Quick take: 1440p is the resolution to target
At 1080p the Core i7-8700K becomes the limiting part (~25% CPU bottleneck), whereas at 4K the RX 6900 XT is the limiting part (~35% GPU bottleneck). We put the target at 1440p: the highest of the usual 16:9 sizes where AAA titles still return 60 FPS, which is above 60. The table below breaks out all twelve resolutions on their own, ultrawide formats included.
As you climb from 1080p to 4K, the load shifts from the processor toward the graphics card: every extra pixel lands on the RX 6900 XT. Here, efficiency moves from 75% at 1080p to 65% at 4K — which shows the part the frame rate depends on at each end.
Down to real numbers: In esports titles like Valorant this pair flies — around 365 FPS at 1080p, plenty for a high-refresh monitor. At the other end, a demanding AAA like Alan Wake 2 drops to ~21 FPS at 4K, which is where the RX 6900 XT's ceiling really shows. Overall, expect about 81 FPS average in AAA games at 1080p and around 40 FPS at 4K.
[CPU] Core i7-8700K
The Core i7-8700K (54/100 on the model's gaming scale) brings 6 cores and 12 threads and determines how many frames per second the system can prepare.
[GPU] RX 6900 XT
On the graphics side, the RX 6900 XT rates 40/100 for gaming in this model. Its 16 GB of GDDR6 set how far it can go on resolution and texture quality before video memory runs short. The higher the resolution, the more of the frame rate depends on it.
On the chemistry of the pair: The graphics card is about 3 years newer than the processor, so watch that the Core i7-8700K doesn't fall short in the most CPU-dependent games. You're combining an Intel platform with an AMD GPU — a perfectly valid mix that imposes no penalty.
DO YOU NEED TO CHANGE ANYTHING?
At 1440p neither part appreciably holds the other back, so there is nothing you need to change. The Core i7-8700K and the RX 6900 XT stand as they are; a 750W supply gives the build headroom.
PRICE OF EACH PART
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SPECIFICATIONS
CATALOGUE DATA[CPU] Intel Core i7-8700K
- Cores6C / 12T
- Clock3.7 – 4.7 GHz
- TDP95 W
- SocketLGA1151
- Single-thread2,714
- Multi-thread13,561
- L3 cache12 MB
[GPU] AMD RX 6900 XT
- VRAM16 GB GDDR6
- Memory bus256-bit
- TDP300 W
- G3D Mark25,541
- Memory bandwidth512 GB/s
BOTTLENECK BY RESOLUTION
SYNERGY · AVERAGE FPSYour CPU (Core i7-8700K) partially limits the RX 6900 XT at 1920x1080. In CPU-heavy scenes you will lose frames. Consider a CPU upgrade or a higher target resolution.
Your CPU (Core i7-8700K) and GPU (RX 6900 XT) are an exceptionally balanced match for gaming at 2560x1440. No realistic component swap would meaningfully improve this build.
Your GPU (RX 6900 XT) is a slight limiting factor at 3440x1440 (Ultrawide 21:9), with limited real-world impact. Most titles will run smoothly.
Your GPU (RX 6900 XT) severely limits the system at 5120x1440 (Super Ultrawide 32:9), leaving the Core i7-8700K heavily underused. A faster GPU would improve performance dramatically.
Your GPU (RX 6900 XT) severely limits the system at 4K, leaving the Core i7-8700K heavily underused. A faster GPU would improve performance dramatically.
ESTIMATED FPS BY GAME
1920x1080SYSTEM DIAGNOSTICS
POWER · VRAM & PCIe · RAMPOWER ESTIMATION
The Core i7-8700K (95W) and RX 6900 XT (300W) add up to roughly 395W under load. Adding 150W for the rest of the system gives 545W, and with a 30% transient margin, 750W is the safe figure.
VIDEO MEMORY AND PCIe
The RX 6900 XT's memory bus (256-bit) and bandwidth (512 GB/s) describe its own video memory, meaning how fast the card reads its 16 GB of GDDR6, not the PCIe link to the processor. The PCIe link depends on the card, the processor and the motherboard slot together; our catalogue does not record PCIe generation or lane count, so the model does not estimate it. It matters most for cards with an eight-lane interface in older PCIe 3.0 boards: check the card's and the board's specifications.
SYSTEM MEMORY
This page assumes 16 GB in dual channel. At 1440p, the resolution recommended above, that meets the model's capacity target of 16 GB (enough for three in four of the games it covers), so more capacity would add little or nothing there. The target stays at 16 GB even at 4K, so a larger kit is for heavy multitasking or mods, not for these games. Memory speed and a second channel act on the processor's ceiling instead: they matter in the games the CPU limits, by an amount that depends on the game, and the calculator lets you enter your own kit.
HOW THIS PAGE IS CALCULATED
ENGINE v2026.08 · 2026-09-11CALCULATED, NOT WRITTEN
Every figure and every sentence comes from the same deterministic engine, driven by the catalogue specifications. That is what makes it reproducible: with the same engine version (2026.08) and the same catalogue, the same pairing always gives the same result. When either changes, the version and date above change with it, and the changelog says why.
WHERE THE DATA COMES FROM
Specifications come from the official AMD, Intel and NVIDIA datasheets together with PassMark and TechPowerUp. The gaming indices are calibrated against frame rates published by review outlets (TechPowerUp, TechSpot / Hardware Unboxed, Tom's Hardware, Gamers Nexus, Digital Foundry) rather than synthetic scores. That data is compiled, not measured here: this site runs no test bench of its own.
STATED LIMITS
Figures estimate native raster performance at high/ultra quality, with no ray tracing, upscaling or frame generation. We do not yet publish an externally validated error margin — the accuracy page states exactly where that stands.
* Affiliate disclosure: the Amazon links exist to show pricing. As an Amazon Associate we earn from qualifying purchases at no extra cost to you. Recommendation order is decided by the engine and does not depend on commission.
TRY WITH YOUR OWN HARDWARE
Customize RAM, resolution, and discover upgrade recommendations.
FREQUENTLY ASKED QUESTIONS
5Does the Intel Core i7-8700K bottleneck the AMD RX 6900 XT?
At 1080p the Core i7-8700K becomes the limiting part (~25% CPU bottleneck), whereas at 4K the RX 6900 XT is the limiting part (~35% GPU bottleneck). Overall, the GPU is the limit at high resolution, with 70% average efficiency across the 12 resolutions our model tests. The resolution we would target with this pair is 1440p, where AAA games average 60 FPS.
How many FPS do the Core i7-8700K and RX 6900 XT get at 1080p?
At 1080p this combination averages about 81 FPS in AAA games and around 234 FPS in esports titles. In Valorant we estimate up to 365 FPS.
Is this pairing good for 4K gaming?
Playable rather than smooth: about 40 FPS on average in AAA titles at 4K, with the RX 6900 XT setting the limit. Upscaling (DLSS, FSR or XeSS) or lower settings are the usual way to reach 60 FPS.
What power supply do I need for the Core i7-8700K and RX 6900 XT?
With an estimated combined draw of 395W across CPU and GPU, we recommend at least a 750W 80+ Gold supply (ideally ATX 3.0) to run with headroom.
Is the RX 6900 XT's 16 GB of VRAM enough?
In the model, 16 GB covers all 11 games it tracks even at 4K with high textures, so video memory is not the constraint for this pairing.