Intel’s upcoming Arrow Lake-S desktop flagship, the Core i9-15900K (renamed to the Core Ultra 9 285K) has been spotted running CPU-Z (via Алексей). The model number and other key details are obscured, but we’re going with the assumption that it’s the Core Ultra 9. The unit is most likely an engineering sample with a base TDP of 125W and a core multiplier range of x40 to x51/x52+, but less than x60. This implies that the CPU will have a single-core boost clock of less than 6.0 GHz and an all-core boost of 5.7 GHz or lower.
The cache specifications line up with what we already know. Each P-core has 3 MB of L2 cache and 4 MB for a cluster of E-cores. The L1D cache comes in at 48 KB and 32 KB for Lion Cove and Skymont, respectively. The L1I cache is shown as 64 KB for both cores.
A screenshot shared by HXL shows a 24-core/24-thread CPU running the Windows Task Manager. Going by the L2 cache size, we assume this to be the Core Ultra 9 285K (15900K). It would seem that the L3 cache will be the same as the Core i9-13900K/14900K, and the lack of hyper-threading is mostly confirmed.
