Will the Ryzen 9 9900X bottleneck the Arc B580?

No. At 1440p the Arc B580 is the limiting part, which is the normal state for a gaming PC. The Ryzen 9 9900X has headroom to spare. This is a model estimate from performance indexes, not a measured FPS loss.

What power supply do I need for a Ryzen 9 9900X and Arc B580?

Sustained gaming load is about 380 W using the Arc B580's measured draw. A 650 W unit is the safe choice.

Is this pair better at 1080p or 4K?

1080p: GPU-limited 25% (GPU-bound (normal)). 1440p: GPU-limited 32% (GPU-bound (normal)). 4K: GPU-limited 47% (CPU overkill).

PCPairs

Ryzen 9 9900X + Arc B580: bottleneck check

32%

GPU-limited at 1440p. GPU-bound (normal).

CPU GPU

The Arc B580 is the part working hardest at 1440p, which is what you want. The Ryzen 9 9900X keeps about 32% in reserve.

By resolution

Resolution	Limiting part	Severity	Verdict
1080p	GPU	25%	GPU-bound (normal)
1440p	GPU	32%	GPU-bound (normal)
4K	GPU	47%	CPU overkill

The Arc B580 is the limit at every resolution and by a wide margin at 4K (47%). The Ryzen 9 9900X is overkill for this card: a faster GPU would give you far more frames than any CPU change.

Specifications

AMD Ryzen 9 9900X
Cores / threads	12 / 24
Max boost	5.6 GHz
Socket	AM5
TDP	120 W manufacturer-published TDP — sustained turbo can be higher · AMD
Released	2024
Gaming index	84 / 100
Multi-core index	90 / 100

Intel Arc B580
VRAM	12 GB
Board power	190 W
Released	2024
1080p index	34.9 / 100
1440p index	29 / 100
4K index	24.1 / 100

Power supply

The Arc B580 measured 185 W average while gaming (237 W highest 20 ms spike, TechPowerUp). With the Ryzen 9 9900X at its TDP of 120 W and about 75 W for the rest of the system, the sustained load is about 380 W. A 650 W unit is the safe choice. Details on the Arc B580 PSU page or try other pairs in the PSU calculator.

Upgrade paths

CPUs that remove the bottleneck

AM5

Cards that use the Ryzen 9 9900X fully

Best CPU for the Arc B580 Best GPU for the Ryzen 9 9900X Arc B580 PSU requirements

Same CPU, other cards

All

Same card, other CPUs

All

Indexes are relative estimates aggregated from published reviews; real results vary by game, settings, memory speed and drivers. Methodology.