I know, Tidux and all, but I believe this is true:
Edit: hardware BC, that is. I believe we'll see PS2 and PS3 games coming to PSN similar to what XBL does with previous XBoxes
Doesn't Xbox have native back-compat with 360 and OG Xbox, though? As in you can have a physical copy of the disc, put it in, then it rips the disc contents to storage and runs the game that way?
X basically uses a software emulator IIRC for OG Xbox and XBO, but they still run natively on local hardware. If PS5 doesn't support PS3 back-compat with that method, and we know chances it'll have a Cell co-processor are almost 0%, then that just leaves streaming.
TBH I don't know how much to believe PS5 won't feature some emulation-base PS3 back-compat. PC has cracked that a good while ago, Sony's own team can certainly manage that with PS5 hardware.
EDIT: Oh you mean hardware-based back-compat as in not emulation? TBH I think they'll use emulation for all the systems, and why not? The tech's matured now, they can optimize their emulations specifically for PS5 and get pretty close to the real deal. Most people who play via emulation do not care about 100% hardware cycle accuracy anyway, otherwise they'd just buy the older consoles or an FPGA-based variant (if available).
I totally believe the controllers inside the system will be capable of those speeds, but for sake of keeping within budget I don't feel like we are going to get a drive that fast, at least not at launch. My other curiousity is though, with these high speed SSD drives, most of them have heatsinks on them, so if they end up making those user replaceable (which I hope to hell they do) I wonder how they are going to accomodate all the different size heat sinks out there.
That's a reasonable concern for the price-related stuff, but again, keep in mind Sony and MS will be choosing one specific drive at large bulk. Now the issue with getting a drive that's both cheap and fast enough would depend on how many NAND modules they set up in parallel; if they went with a 1TB drive that's simply 2x 512GB modules for example, they won't hit near the maximum speed of the controller's limits. But they would save money that way vs. 8x 128GB modules, or 16x 64GB modules, etc. etc., per drive.
But yeah, I can see where you're coming from about the pricing. It's kind of why I think IF they try going with a drive to get around that bandwidth, out of necessity it'd have to be custom, because equivalent 1TB QLC NAND drives on the market right now are not getting anywhere near 6-8GB/s. And you bring up heat as well, which is important, which means that kind of drive in a console would very likely be tightly connected to the board and (likey) non-replaceable. That way it could be cooled with the general system cooling solution the consoles will use.
Unfortunately I don't know what the read/write speeds of general NAND chips are, but I found an article saying it can range from generally 1Gbps (128 MB/s) (some lower than that actually) to 3D NAND chips hitting an average of about 1.4Gbps (176 MB/s). Newer tech has some pushing closer to 3Gbps (384 MB/s).
So say the custom drives are using these newest of new chips (not unreasonable; Universal Flash Storage cards probably use chips like this since even Gen 2 UFS can hit around 1165 MB/s); to saturate say 7 GB/s bandwidth they'd need about 18-19 of those chips in parallel access. That'd at least handle the bandwidth issue, but not necessarily the capacity issue (each of those chips'd need to be about 64GB in size; technically 56.8 but chips aren't manufactured at that capacity).
But that'd be the best outcome; with 1.4Gbps chips they'd need 40 of chose chips, at 32GB capacities. And 1Gbps chips? About 55 chips (odd number, so probably 56), but the problem there is they'd need about 18GB capacity chips. So really either 16GB (they don't hit 1TB), 24GB (not as commonly produced) or 32GB (they'd push over 1.7TB of storage). That's probably the worst option, let alone NAND with even lower Gbps.
So yeah, it might be more economical if they're targeting closer to 3 GB/s speed with a 1TB custom drive sort of like AMD's SSG cards; best option then would be 8 chips in parallel, 3Gbps I/O, 128GB capacity. Or if they upped it to 12 of those chips in parallel, they could get around 4.6 GB/s. In either case, more cost-effective and TDP-friendly than targeting 7 GB/s - 8 GB/s, that's for sure.
...That's considering other specs for XSX in particular and figuring what the BOM for those would be, plus the power draw. If PS5 is closer to the 9.2TF - 9.7TF range, they would actually have more headroom for a faster SSD with the setup I mentioned above than Microsoft, because of the savings on TDP due to less-demanding GPU and less GDDR6 memory. Not to mention the price savings; all of that could be shifted to more NAND in parallel for a faster custom SSG-style SSD drive, even if both systems use a similar setup fundamentally speaking and go for same size (1TB).
At least that's how I figure it could go. Would still necessitate need for an optional drive, probably internal M.2, and regardless of whatever speed the custom drive would be (3-4 GB/s or 7-8 GB/s), would be noticeably slower than that. But that's okay, since it'd be mainly for cold storage.
Technically speaking, this kind of custom drive would be a good way for Sony and MS to create another potential peripheral segment; they'd use smart memory management regardless for them but power users would eventually start to wear them down, and desire a replacement. So those drives COULD be replaceable, but only with custom peripheral drives from Sony and MS. Honestly don't think this would be a big issue; people already buy multiple controllers, headphone sets, and other peripherals as-is. At least the custom drive brings something new to the game.