{"slug": "sparkle-arc-pro-b60-only-150-gb-s-vram-bandwidth-spec-456", "title": "Sparkle Arc Pro B60: only 150 GB/s VRAM bandwidth (spec 456)", "summary": "A Sparkle Arc Pro B60 owner reports the card delivering only 150 GB/s of VRAM bandwidth in clpeak's --global-memory-bandwidth test, against a 456 GB/s specification, and is asking other B60 owners to run the same test to confirm. The owner says dense LLMs run at roughly half the speed of other reports, with Qwen3-27B Q4_K_M reaching 8.6 t/s versus 16 t/s on other B60s using the same llama.cpp build and flags. The discrepancy matters because if the 150 GB/s figure is reproducible, the card's memory bandwidth is about a third of its rated spec and would explain the slower token generation.", "body_md": "I’ve been testing dense LLMs on my B60 and they seem to run at half the speed of some other reports - Qwen3.8-27B Q4_K_M at 8.6 t/s, against 16 t/s on other B60s with the same llama.cpp build and flags.\n\nTroubleshooting with claude led me to a potential issue with vram bandwidth.\n\nTesting with clpeak –global-memory-bandwidth I got the result - 150 GB/s.\n\nIf another B60 owner can run the same test and let me know I would really appreciate it.", "url": "https://wpnews.pro/news/sparkle-arc-pro-b60-only-150-gb-s-vram-bandwidth-spec-456", "canonical_source": "https://forum.level1techs.com/t/sparkle-arc-pro-b60-only-150-gb-s-vram-bandwidth-spec-456/259325#post_1", "published_at": "2026-10-23 10:54:53+00:00", "updated_at": "2026-10-23 11:10:55.120082+00:00", "lang": "en", "topics": ["ai-infrastructure", "ai-chips", "large-language-models"], "entities": ["Sparkle", "Arc Pro B60", "Qwen3-27B", "llama.cpp", "clpeak", "Claude"], "also_reported_by": [], "alternates": {"html": "https://wpnews.pro/news/sparkle-arc-pro-b60-only-150-gb-s-vram-bandwidth-spec-456", "markdown": "https://wpnews.pro/news/sparkle-arc-pro-b60-only-150-gb-s-vram-bandwidth-spec-456.md", "text": "https://wpnews.pro/news/sparkle-arc-pro-b60-only-150-gb-s-vram-bandwidth-spec-456.txt", "jsonld": "https://wpnews.pro/news/sparkle-arc-pro-b60-only-150-gb-s-vram-bandwidth-spec-456.jsonld"}}