Intel is rumored to be releasing another Core i9 Extreme processor, though the new SKU, if it does in fact exist, is a bit of an oddity. For one thing, the upcoming Core i9-9990XE will not be sold through retail channels, and will instead only be made available to system integrators through a closed auction, according to the rumor.
That is a bit unusual in and of itself—even the limited edition Core i7-8086K commemorating the 40th anniversary of the 8086 processor that kick started the x86 era is a retail chip. It's not clear why Intel would make the Core i9-9990XE an exclusive part that is presumably tough to obtain, though it probably has to do with the special binning.
On the topic of binning, the Core i9-9990XE is a 14-core/28-thread processor, according to Anandtech, which has seen related documentation and supporting information from multiple sources. In contrast, the Core i9-9980XE is an 18-core/36-thread CPU.
In other words, the highest model number in Intel's Basin Falls lineup will not have the most cores and threads to throw at workloads. Instead, it appears to be a hyper-binned and faster-clocked Core i9-9940X, which is also a 14-core/28-thread CPU. Whereas the Core i9-9940X has a 3.3GHz base clock and 4.5GHz boost clock, the Core i9-9990XE has a speedier 4GHz base clock and 5GHz boost clock.
The cache arrangement is not known at this time. For reference, the Core i9-9940X has 1.375MB of L3 cache per core, giving it 19.25MB of total L3 cache. The Core i9-9980XE, meanwhile, bumps that up to 1.375MB per core, for a total of 24.75MB of L3 cache.
The other thing that is interesting here is the TDP. Instead of a 165W TDP like each of the other Basin Falls chips, it gets jacked up to 255W on the Core i9-9990XE. That will require some heavy-duty cooling, as well as a motherboard that can supply 420 amps to the CPU.
There is no information available on pricing, because that hasn't been determined yet. Pricing will come down to what system integrators are willing to pay during the auctions, which will be held once per quarter.