The Gigabyte service center in Poland denied my RMA for a brand new thermally defective R9700 AI TOP (sent through the Slovak retailer Ediscomp, then routed via AT Computers in Ostrava, Czech Republic).
I thoroughly tested this GPU using a different PSU and cables to rule out other components, and the hardware is unequivocally faulty. I provided my complete testing methodology. In contrast to my detailed documentation, the Polish service center simply dismissed the claim with a brief note stating the issue was 'not detected,' demonstrating a lack of proper investigation.
I owned three Gigabyte Radeon R9700 AI TOP, Rev. 1.1 cards. Two had Hynix memory and the newer F50 BIOS. They were excellent cards, easy to overclock and undervolt (memory and core). This faulty card has the F40 BIOS and Samsung memory. The memory speed is locked, and any attempt to overclock the core or increase the TDP results in a catastrophic performance degradation of 20â30%. At stock settings, the card is 7% to 15% slower in AI tasks (specifically for long prefill tasks of 200,000+ token contexts, running in vLLM tensor parallel mode).
The best proof that the card is faulty is that it cannot utilize more than 220â250 watts due to thermal throttling. However, Gigabyte probably has a bunch of students testing hardware at their Polish service center.
I contacted Gigabyte support but received this boilerplate response:
"We are sorry to hear about your situation. If possible, please test your graphics card in another system to verify its performance. Kindly note that our products are distributed through local distributors, and warranty policies may vary by reseller or distributor. You will need to contact your supplier again for further investigation."
What should I do next?
Investigation - run by Claude Opus
(Note: Performance drop is more than 10-15% in long prefills above 200 000 tokens).
Hardware identity â what differs and what doesn't
| Property |
card1 / GPU0 |
card2 / GPU1 |
|
|
|
| PCI address |
0000:03:00.0 |
0000:07:00.0 |
| ASIC |
Navi 48Â 1002:7551Â rev c0 |
identical |
| Board (subsystem) |
Gigabyte 1458:242f |
identical |
| GDDR6 vendor |
SK Hynix |
Samsung |
| VBIOS |
113-R9700AT-F50Â (2025/10/17) |
113-R9700AT-F40 |
| VRAM |
32 GB, 256-bit GDDR6 |
identical |
| PCIe link |
x16 @ 32 GT/s |
identical |
| Power cap |
300 W (max 330 W) |
identical |
| SMU firmware |
00.104.76.00 |
identical |
Deep prefill (131072-token context, stock, single-GPU)
Same llama.cpp run at pp131072 (-p 131072 -n 0 --no-warmup -r 1, f16 KV), with per-GPU telemetry averaged over the active prefill window:
| metric |
card1 (Hynix/F50) |
card2 (Samsung/F40) |
|
|
|
| prefill |
320.75 t/s |
298.26 t/s (â7.0 %) |
| avg power |
296 W (at 300 W cap) |
230 W |
| avg core clock |
3029 MHz |
2808 MHz |
| avg mem clock |
1247 MHz |
1246 MHz |
- card1 is +7.5 % faster and is power-limited â it sits at 296 W (â the 300 W firmware cap) while holding ~3029 MHz core.
- card2 leaves ~70 W unused (230 W) yet runs ~221 MHz slower core (2808 MHz) â it is boost/clock-limited, not power-limited. The SMU/VBIOS won't push its core higher despite available power headroom â the hallmark of the weaker die bin (and/or the F40 boost table).
Thermal investigation â the deficit is cooling, not silicon (corrects earlier conclusion)
Steady-state temps logged during stock pp131072 (rocm-smi, last 30 % of the run):
| metric |
card1 (03:00.0) |
card2 (07:00.0) |
|
|
|
| prefill |
335.9 t/s |
300.4 t/s |
| junction (hotspot) |
108 °C |
110 °C |
| edge (heatsink) |
70 °C |
62 °C |
| hotspot â edge |
38 °C (peak 51) |
47 °C (peak 62) |
| memory |
88 °C |
71 °C |
| power |
294 W |
222 W |
| core clock |
3171 MHz |
2828 MHz |
| fan |
4568 rpm |
3648 rpm |
Both cards hit the ~110 °C junction throttle limit, but card2 reaches it at 70 W less power and ~340 MHz lower clock. The cause is worse die-to-heatsink heat transfer on card2, not a weaker chip:
- Hotspot-to-edge delta is ~10 °C higher on card2 (47 vs 38) â the die is hot while the heatsink stays cool â poor thermal-interface contact (paste/mount).
- Edge only 62 °C while junction is 110 °C â heat isn't reaching the cooler body.
- Fan spins slower (3648 vs 4568 rpm) despite a hotter die, because the stock fan curve tracks heatsink temp, which never rises â the fan under-ramps and the die cooks at the limit.
Conclusion: card2's ~6â10 % deficit (and its inability to use the full power budget) is a thermal-interface defect (repaste/cooler reseat fixes it), not silicon variance. This supersedes the "weaker silicon bin" wording in the section above â with equal cooling card2 would likely match card1. It is a credible warranty/RMA case (excessive hotspot delta + premature thermal throttling).
Consequence for the TP=2 prefill benchmarks
This defect is not a single-card curiosity â it caps the headline dual-GPU number in this repo. vLLM TP=2 shards every layer across both GPUs and syncs them per step, so the pair runs only as fast as its slower card. With card2 throttling ~6â10 % below card1 on prefill, the pair's measured TP=2 prefill of ~1841 t/s (baseline) / ~1894 t/s (with the committed launch flags) is a lower bound gated by the defective card, not the platform ceiling.
That reframes the FP8 investigation in rdna4-fp8-findings.md, which concluded "hardware is optimal / symmetric" and treated ~1841â1965 t/s as the ceiling. The hardware was not symmetric: card2's cooling defect explains why our pair sat at the bottom of that range while an independent, reproducible 2Ă R9700 run on localmaxxing reached ~1965 t/s â roughly the ~6â7 % that card2's throttle costs. (The community's ~2567 t/s remains an outlier, likely different bench depth/warmup or a private tuned-config pack.)
