Gadgetory

as SSDs or solid-state drives have evolved some of the components have become much more sophisticated like the controllers on board that have gone from rudimentary single-core Affairs to multi-core processors with huge amounts of RAM and complex algorithms built into their firmware but the foundation of nearly every SSD the NAND flash memory that actually stores your data has actually gotten progressively worse in some big ways we went from high speed and super reliable SLC flash which stores only a single one or zero to each cell to dual er mlc to Triple A or TLC two finally today this is the Intel 660 P the first consumer SSD with qlc flash which is notable for its ability to store four bits per cell that means 16 separate voltage levels this gives it fantastic affordability especially for an nvme SSD but my mama always told me if it seems too good to be true it probably is so let's take a look at the pros and cons for today only you can pick up PC building simulator on chrono GG for $15 us so check it and all of chrono GG's games out at the link in the video description let's start with the bad stuff first up is that QL cement has lower endurance than PLC which means that all other things being equal it doesn't last for as long why well I'm glad you asked because it's science time with pictures this is really important every time a cell gets written to a voltage pulse is sent through the control gate which creates an electric field which agitates the electrons causing them to move through the silicon dioxide layer towards the floating gate that their layer wears out a tiny bit every time a program erase command is sent to the cell causing some of these shifting electrons to get stuck inside of it which means that it will have and more importantly continue accumulating a progressively more negative charge now this gets compensated for by applying ever slightly higher positive voltage to the cell to get it to the desired voltage state now at some point the voltage levels start bordering those required by the adjacent states to the point where it takes too long to distinguish what's what and that block will get taken out behind the barn old yeller style now the fewer layers that there are inside of a cell the wider the spare voltages in between the states so then as you can imagine with qlc the point of cannot deal with this anymore GD cell come sooner than with TLC and especially mlc or SLC much sooner second bad stuffs qlc is also slower which like wait a second why why is that denser processor transistors are better increasing the areal density of a hard drive platter is better shouldn't more data density and NAND flash be better unfortunately no it's actually the opposite you see with hard drives cramming more data into the same surface area increases the read and the write speeds because the platter rotates at a constant speed usually 5400 to 7200 rpm or so which means that the more densely the bits are packed the more of them pass under the head in a given amount of time more bits is more data so denser in this case is better that is as long as you can keep your read error rate under control but that's a little separate discussion back to SSDs for now when an SSD cell is accessed a distinction between the multiple voltage levels needs to be made and the number of states that you need to sift through goes up exponentially with the number of layers that it holds so the more layers the more states and the longer it takes to get a reading for example it takes 25 microseconds to read for SLC 54 MLC 75 for TLC and a hundred for qlc and it's the same story with writes except the performance drop off is even worse finally big problem number three here we're getting into this drive specifically the advertised write speeds are kind of hax because there isn't really a right way to do it you see this drive treats part of its qlc cells as SLC flash as a kind of cache so remember SLC that's the fastest kind and the exact size of this cache scales depending on how much you've filled up your drive so so then by this point in the video you're probably thinking all right well then qlc has a severe case of the no bueno x' and this here 660 P Drive is a no me gusta but know everything that we just said was in theory now it's time for a little bit of reality so to put those hacks right numbers to the test and see just how bad the whole SLC cache with slower qlc behind it deal affects things we hit this drive with a full range right through HD tune Pro and guess what halfway through the performance plummeted to below that of a hard drive and then stayed there for consecutive runs after a brief spike on each run but then we observed this behavior only after more than half of the drives capacity was written to something that was supposed to happen earlier on in the test which got us thinking maybe the caching algorithm was actually working in the background shuffling data over to the slower key OC cells so we tried running the cache flusher utility from Intel's SSD toolbox during the test and observed its progress bar actually going backwards while our benchmark was showing throughput spikes when we ran the cache flush after doing a full capacity right it took about 20 minutes total and then restored the drive to its full write speed now when we tested Intel's own higher tier and noticeably more expensive 760 P we also saw write performance drop during the first run after it ran at a cache and dropped further on consecutive runs but as you'd expect it remained much faster in the same scenarios than its lesser sibling okay so that's synthetic tests but what about a real life but edge case let's copy a 250 gig steam folder over to the 660 P there we go same thing it starts off fast then it dips dip dips and plummets like OCC stock before their bankruptcy in 2013 when compared to a similarly priced 840 Evo that they managed to maintain a steady 485 megabytes per second and completed the copy in only 8 minutes and 45 seconds this thing took a staggering 23 and a half minutes remember when I said qlc is slow without a cache well behold the worst case scenario slower than a hard drive meanwhile the TLC equipped 7 6 DP after starting off strong dropped to a more stable 560 megabytes per second and then maintained that completing the same transfer in 8 minutes 20 seconds now let's get more realistic all of the theory crafting we've done so far failed to have any tangible effect on our other tests game load times were about the same between all three drives and when we ran the PC market storage subsystem bench we had to double check that we didn't accidentally test the same drive twice so a typical LTT video takes up about 24 gigs for a seven and a half minutes which takes about 20 minutes to render so just over one gigabyte per second of right so we wouldn't have any performance drop unless we were filling up our 660 P to the brim leaving no room for SLC caching which by the way we don't recommend filling up any SSD also keep in mind that during normal usage your SSD is idle the vast majority of the time so that cache flush algorithm will have all the time it needs to quietly restore your SSD in the background so now that we've covered the worst case for qlc performance and how the SLC cache can give it boosts of higher performance let's talk longevity when compared to intel's own TLC 760 p drive this thing is rated for 1/3 the longevity but looking closer this actually assumes about a hundred gigabytes of writes per day that is basically equivalent to rendering out a couple of LTT videos and installing doom on your computer every day it's not a realistic use case for the average consumer so to sum things up if you were to install a 660 p SSD in your system unless you're using it for something that it wasn't designed for like as a cache for your nas or your hard drive all things considered you would save a few bucks since this is Intel we're talking about they're not generally known for their aggressive pricing this thing out competes other nvme drives on price and you'd probably never notice that you're running qlc because of the SLC cache and you'd have a five-year warranty to give you peace of mind unless of course the drive hits its total drive rights limit before that five years run zone so the enthusiast in me has some serious misgivings about this move for the nand storage industry but this product wasn't made for me that's opting and I haven't seen anything about this drive to suggest that it won't do a good job for its intended audience thanks to the firmware and controller trickery that we alluded to earlier I guess that's okay even if it makes me uncomfortable do you need to create a beautiful functional website without the hassle check out Squarespace their all-in-one platform makes it easy to get up and running quickly they've got award-winning templates that you can use as starting points for a wide range of projects and if you're 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