Two Top CPUs, One Workload That Separates Them
AMD’s Ryzen 7 9800X3D and Intel’s Core Ultra 7 265K sit at similar price points and target the same high-performance desktop market, but video encoding is the one workload where their architectural differences stop being theoretical and start showing up in benchmark results.
What the Architecture Tells You Before Testing Begins
The 9800X3D is built on AMD’s Zen 5 core architecture with 3D V-Cache stacked on top – 96MB of L3 cache total. That cache is the reason the chip dominates gaming benchmarks, but for video encoding, it offers little advantage. Encoding workloads are not cache-sensitive in the same way gaming is. They are throughput-sensitive, meaning the raw compute pipeline and clock speeds matter far more than how much data can sit close to the cores.
The Core Ultra 7 265K takes a different approach entirely. Intel’s Arrow Lake design separates compute tiles and uses a hybrid architecture with 8 P-cores running up to 5.5GHz and 12 E-cores handling background tasks. In encoding scenarios, those E-cores are not idle – they absorb lighter threading work while the P-cores push through the heavy decode and encode passes. The total core count of 20 versus the 9800X3D’s 8 cores is where the gap starts to make sense.
Software encoding through x264 and x265 scales well with core count, which is why multi-core performance numbers are worth scrutinizing here. The 9800X3D maxes out at 8 cores with simultaneous multithreading, giving it 16 threads. The 265K brings 20 cores and 20 threads (P-cores are not hyperthreaded in Arrow Lake). On pure thread count alone, Intel has the structural advantage for this type of workload.
Hardware encoding through Intel Quick Sync is also a factor that cannot be ignored. The 265K includes Intel’s latest Quick Sync engine, which handles H.264, H.265, and AV1 encoding in dedicated silicon. AMD’s integrated media engine on the 9800X3D also supports hardware acceleration, but Intel’s Quick Sync implementation has historically been more mature, particularly for streaming and content creation pipelines that prioritize speed over absolute quality.
Benchmark Results Across Common Encoding Scenarios
In x265 software encoding at medium preset – the most common test for raw CPU throughput – the Core Ultra 7 265K pulls ahead by a margin that matters for production work. The 265K encodes faster due to the higher thread count, with the performance difference becoming more pronounced as the preset slows down and the encoder leans harder on parallel processing. At the slow preset, the gap widens further. The 9800X3D’s 8-core configuration hits a ceiling that the 265K’s 20-core setup simply does not reach.
x264 encoding tells a similar story, though the gap narrows slightly at faster presets where single-core speed plays a larger role. The 9800X3D’s Zen 5 cores are strong per-clock performers, and at presets like “fast” or “veryfast,” the chip stays competitive. Push into “medium” or “slow” territory and the thread count advantage of the 265K reasserts itself. For anyone encoding long-form video content – full episodes, short films, YouTube uploads over 30 minutes – that difference compounds over time into real workflow hours saved.
AV1 software encoding through SVT-AV1 is where the results get most decisive. AV1 encoding is computationally expensive and scales aggressively with thread count. The 265K’s 20-thread configuration handles SVT-AV1 workloads with noticeably higher frames-per-second throughput than the 9800X3D. This matters now that AV1 has become a serious delivery format – YouTube, Netflix, and Discord all use it, and content creators targeting those platforms increasingly need fast AV1 encode pipelines.
Hardware encoding via Quick Sync on the 265K is in a different category entirely when speed is the only priority. Quick Sync AV1 encoding runs at speeds that no software encoder can match, though quality at equivalent bitrates falls below what SVT-AV1 produces at slower presets. For live streaming or fast review exports, Quick Sync wins. For archive-quality encodes or final delivery, software encoding quality still holds an edge. AMD’s hardware encoder produces acceptable results, but Quick Sync’s speed advantage in hardware AV1 is measurable and consistent.
Handbrake, which many general users rely on for video conversion, reflects the same pattern. The 265K completes encode jobs faster across H.264 and H.265 profiles, with the gap sitting comfortably in Intel’s favor for anything longer than a few minutes of source footage. The 9800X3D is not slow – it is a capable encoding chip – but it was not designed with this workload as a priority, and the benchmark results make that clear.
Thermal Behavior Under Sustained Encoding Load
One area where the 9800X3D actually holds an advantage is thermal stability under sustained encoding workloads. Video encoding runs for minutes or hours at a time, and the 9800X3D draws less total power under that kind of sustained all-core load than the 265K, which can pull aggressively when all 20 cores are engaged. The 265K requires a capable cooler and adequate case airflow to maintain peak performance without thermal throttling. The 9800X3D is more forgiving in thermally constrained builds.
For a PC builder who wants a single CPU that handles both competitive gaming and a content creation side workflow, the choice becomes harder than the encoding benchmarks alone suggest. The 9800X3D dominates gaming frame rates and handles encoding well enough for occasional use. The 265K wins encoding decisively but trails in gaming scenarios where cache-sensitive workloads reward AMD’s 3D V-Cache design. If video encoding is a daily professional requirement rather than an occasional task, the 265K’s throughput advantage is real enough to drive the decision – but anyone treating the 9800X3D as purely a gaming chip is leaving the full picture on the table.
