CPU_VS_GPU / 2026-09-11
Intel Core Ultra 5 245KFvsNVIDIA RTX 4080
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 Ultra 5 245KF) and GPU (RTX 4080) 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 Ultra 5 245KF
- GRAPHICSNVIDIA RTX 4080
- MEMORY16GB DDR4/DDR5
- RESOLUTION2560x1440
Average across the demanding titles at 2560x1440.
Average across the competitive titles, where the processor leads.
What the build draws (595 W) plus headroom.
DEEP-DIVE ANALYSIS
GENERATED BY THE ENGINEAre the Intel Core Ultra 5 245KF and the NVIDIA RTX 4080 a good match? To find out we modelled the pair from 1080p up to 4K, cross-referencing the model's gaming scores for the CPU (83/100) and the GPU (67/100), calibrated against measured benchmarks rather than synthetic scores, with the demand profile of each game.
Verdict: play this build at 4K
At 1080p the RTX 4080 has power to spare and sits partly idle, whereas at 4K the RTX 4080 is the limiting part (~27% GPU bottleneck). We put the target at 4K: the highest of the usual 16:9 sizes where AAA titles still return 62 FPS, which is above 60. The table below breaks out all twelve resolutions on their own, ultrawide formats included.
Resolution reshuffles the priorities. At 1080p the Core Ultra 5 245KF's single-thread speed calls the shots; at 4K it's the raw muscle of the RTX 4080 that matters. That shift shows up in the numbers: 66% efficiency at 1080p versus 73% at 4K.
In esports titles like Valorant this pair flies — around 773 FPS at 1080p, plenty for a high-refresh monitor. At the other end, a demanding AAA like Alan Wake 2 drops to ~40 FPS at 4K, which is where the RTX 4080's ceiling really shows. Overall, expect about 118 FPS average in AAA games at 1080p and around 62 FPS at 4K.
[CPU] Core Ultra 5 245KF
The Core Ultra 5 245KF scores 83/100 on this model's gaming scale, with 14 cores and 14 threads. In this pairing its job is to serve frames fast enough to never leave the graphics card waiting.
[GPU] RTX 4080
On the graphics side, the RTX 4080 rates 67/100 for gaming in this model. Its 16 GB of GDDR6X 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.
A detail that's easy to overlook: Both parts come from nearby generations, which usually means a natural pairing with no platform surprises. You're combining an Intel platform with an NVIDIA 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 Ultra 5 245KF and the RTX 4080 stand as they are; an 800W supply gives the build headroom.
PRICE OF EACH PART
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SPECIFICATIONS
CATALOGUE DATA[CPU] Intel Core Ultra 5 245KF
- Cores14C / 14T
- Clock4.2 – 5.2 GHz
- TDP125 W
- SocketLGA1851
- Single-thread4,713
- Multi-thread43,109
- L3 cache24 MB
[GPU] NVIDIA RTX 4080
- VRAM16 GB GDDR6X
- Memory bus256-bit
- TDP320 W
- G3D Mark34,650
- Memory bandwidth716.8 GB/s
BOTTLENECK BY RESOLUTION
SYNERGY · AVERAGE FPSYour GPU (RTX 4080) has far more capacity than 1920x1080 can use: around 34% of it sits idle. Stepping up to 1440p or 4K would put that capacity to work at the cost of some frames: you gain sharpness, not speed.
Your CPU (Core Ultra 5 245KF) and GPU (RTX 4080) are an exceptionally balanced match for gaming at 2560x1440. No realistic component swap would meaningfully improve this build.
Your GPU (RTX 4080) is a slight limiting factor at 3440x1440 (Ultrawide 21:9), with limited real-world impact. Most titles will run smoothly.
Your GPU (RTX 4080) is the limiting factor at 5120x1440 (Super Ultrawide 32:9). In graphically demanding titles you will see lower frame rates; a faster GPU would deliver a clear improvement.
Your GPU (RTX 4080) is the limiting factor at 4K. In graphically demanding titles you will see lower frame rates; a faster GPU would deliver a clear improvement.
ESTIMATED FPS BY GAME
1920x1080SYSTEM DIAGNOSTICS
POWER · VRAM & PCIe · RAMPOWER ESTIMATION
The Core Ultra 5 245KF (125W) and RTX 4080 (320W) add up to roughly 445W under load. Adding 150W for the rest of the system gives 595W, and with a 30% transient margin, 800W is the safe figure.
VIDEO MEMORY AND PCIe
The RTX 4080's memory bus (256-bit) and bandwidth (716.8 GB/s) describe its own video memory, meaning how fast the card reads its 16 GB of GDDR6X, 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 4K, 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. 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
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FREQUENTLY ASKED QUESTIONS
5Does the Intel Core Ultra 5 245KF bottleneck the NVIDIA RTX 4080?
At 1080p the RTX 4080 has power to spare and sits partly idle, whereas at 4K the RTX 4080 is the limiting part (~27% GPU bottleneck). Overall, the GPU is the limit at high resolution, with 75% average efficiency across the 12 resolutions our model tests. The resolution we would target with this pair is 4K, where AAA games average 62 FPS.
How many FPS do the Core Ultra 5 245KF and RTX 4080 get at 1080p?
At 1080p this combination averages about 118 FPS in AAA games and around 456 FPS in esports titles. In Valorant we estimate up to 773 FPS.
Is this pairing good for 4K gaming?
Yes. At 4K this pairing averages about 62 FPS in AAA titles, at or above the 60 FPS we treat as smooth, with the RTX 4080 setting the limit.
What power supply do I need for the Core Ultra 5 245KF and RTX 4080?
With an estimated combined draw of 445W across CPU and GPU, we recommend at least an 800W 80+ Gold supply (ideally ATX 3.0) to run with headroom.
Is the RTX 4080'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.