Jim Keller's Tenstorrent is downgrading Blackhole p150 cards from 140 to 120 tensor cores via firmware update — will ship cards with 120 tensor cores going forward, company claims existing users should expect 1-2% performance drop

Unlike many startups producing nothing but vaporware, Jim Keller's TensTorrent has actually delivered impressive-looking RISC-V AI accelerators, but there could be some trouble brewing. Starting with firmware version 19.5.0, the firm has now chopped the tensor core count on Blackhole p150 cards from 140 to 120, affecting both new cards and existing units already in customers' hands.

The news was apparently communicated to customers via email, with the same wording present on the firmware update's GitHub page. Tenstorrent isn't elaborating on why the change was made, leaving existing and potential buyers scratching their heads. The quote follows:

The statement seems to raise more questions than answers. Twenty out of 140 cores is about a 14% chop. When comparing the old and new Blackhole p150 product pages on Tenstorrent's site, the raw compute capacity is 774 vs 664 TFLOPS, a change that appears substantial, especially in the context of multi-card setups like the QuietBox. And yet Tenstorrent claims that in practice, for one card, this should amount to a 1-2% performance delta when using TT-Metalium, a low-level developer kit that operates close to the hardware.

One user in the company's Discord server raised the question of whether the SDK even fully utilizes the underlying hardware to begin with, while another remarked that changing the core grid layout and timing can negatively affect existing, tested code. It's not that existing users have much of a choice, either: update the firmware and lose cores, or lose out on new features of a nascent, in-development product. Predictably, jokes about the 14% core chop were plentiful.

One can but hypothesize as to why the change was needed. Perhaps Tenstorrent wasn't getting good yields for their Blackhole chips, but that would be an odd twist given that they're reportedly manufactured on a 6-nm process, pretty mature technology by today's standards. Tenstorrent is already in conversations with multiple 2-nm chip manufacturers for its next generation of products, but in the meantime, has yet to deliver its upcoming two-chip, 64 GB Blackhole p300.

Tenstorrent's existing lineup of Blackhole products comprises AI accelerator cards for workstations and developers wanting to run AI models locally. They're actually reasonably priced, as the p150 model can deliver 664 TFLOPs and comes with 32 GB of VRAM for just $1,399, or about one-third the price of a single RTX 5090, while theoretically delivering several times the performance. The cards can be wired together to pool VRAM, too, and the chips combine CPU and tensor cores on the same die, bypassing a number of limitations of conventional designs.

It's reasonable to expect some turbulence, as it's exceedingly difficult to create an entire new AI accelerator plus its software, on an unusual architecture, with an unusual chip layout. TensTorrent's current aim at small-scale AI accelerators for small businesses, laboratories, and individuals may well carve out a niche of the market and offer dividends in the long run, so long as turbulence is kept to a minimum.

Follow Tom's Hardware on Google News, or add us as a preferred source, to get our latest news, analysis, & reviews in your feeds.