AMD's revolutionary V-Cache for Ryzen: Everything you need to know - kimbroughhimend

AMD's mic-drop moment at Computex was the word of its closely guarded "V-Cache" applied science, which would enable chip stacking along Ryzen CPUs.

PCWorld interviewed AMD's Surface-to-air missile Naffziger about V-Stash. We boiled down that conversation into a baker's dozen of key things you require to know.

amd computex 2021 show keynote 3d chiplet technology page 06 — The V-Cache in the CPU above sits above the alive Processor's L3 cache. Additive Si adjacent to it is used to constrain the give way and take heat to the heat spreader.

What is V-Cache?

V-Lay away uses TSMC's SoIC (System on Coeducational Chips) chip-stacking engineering to add 64MB of SRAM L3 cache to the compute dies of existing Zen 3-based Ryzen CPUs. That will basically triple the amount of cache to an insane 192MB of L3 for the 12-meat and 16-core versions of AMD's CPUs.

V-Memory cache will seminal fluid to Zen 3-based Ryzen CPUs later this twelvemonth

There was a little confusion as to which CPUs would get V-Hive up, and when, arsenic AMD Chief operating officer Lisa Su delayed a prototype Ryzen with the engineering science. The ship's company has since confirmed that yes, V-Cache bequeath come to high-end, Dose 3-based Ryzen CPUs at the end of the year.

amdppt2 100585245 orig — AMD previously used TSV (Through-Si Via) technology in its first Vega GPU's HBM memory. As you can see, it channels through the silicon itself to colligate to the next layer set.

How is V-Cache connected?

The item-by-item 64MB SRAM cache will be stacked on each compute die over the existing L3 cache and be connected using a technology known as Through-Silicon Via, which connects stacked chips victimisation a tunneling system. This isn't AMD's first experience with TSV: The original Vega GPU with its HBM memory also used TSV technology.

Latency shouldn't be an issue

One concern with the larger amount of L3 is latency, or delay, as the CPU fetches book of instructions or data from the cache. AMD's Naffziger said that shouldn't be a problem with V-Hoard, because the TSV construction offers a more direct route to the cache.

How fast will V-Cache embody?

AMD is touting a lambas-dropping 2TBps and beyond of bandwidth for V-Cache. That's insanely fast. Atomic number 3 a compare, Intel's 2013-era Core i7-4770R "Crystal Well" flake, which featured an impressive 128MB of eDRAM L4, offered about 100GBps of bandwidth at the metre.

Can you stack more V-Cache on meridian of each otherwise?

Although that may non take place with the first-class honours degree Ryzen chips with V-Cache, there's nothing that would prevent the stacking of V-Cache.

Won't V-Stash pull through harder to cool the CPU?

IT mightiness seem crazy to winning a calefactive CPU die and throw a silicon blanket over IT, block its touch with the thermal interface material and rut spreader. AMD's Naffziger said that won't embody an issue, because the factual SRAM L3 sits on the existing L3 cache on the die. The actual C.P.U. cores that generate most of the heating will have a stratum of silicon that volition convey heat to the TIM and heat spreader.

Developers don't need to optimise for it

The V-Cache will function in a seamless manner to applications and games, so developers don't need to come out patches or software updates to consider advantage of it. Fire up a game or app, and it'll just see a bulky ol' bucket of 192MB of L3 cache.

amd computex 2021 show keynote 3d chiplet technology page 08 — AMD said about a 15 percentage extrusion was seen from righteous the V-Cache.

What bequeath V-Cache make faster?

AMD til now has showed off very impressive gains in gaming using a standard Ryzen against one with V-Cache locked at 4GHz. AMD showed gains from 4 percent to 25 percent just from the additional L3 cache. That's or so a 15-percent gain on the average, which the keep company said is tantamount to an entire people CPU change.

Will V-Memory cache help make anything else go faster?

So far, AMD has declined to list performance increases in anything otherwise gambling, but we mistrust that's because it's saving that for later. Naffziger did say you force out flavour at already published studies of performance increases from additional L3 cache. We believe V-Cache could declare oneself very good performance increases depending along the application, but we'll have to hold and see before we behind say certainly.

Will V-Cache work with existing AM4 motherboards?

AMD did not order which motherboard sockets the first V-Cache Ryzen CPUs will break down into, just we'atomic number 75 jolly certain it'll atomic number 4 the existing stock of AM4 motherboards. That would be zealous news for upgraders who deprivation to eke impermissible i more CPU connected an existent system. Naffziger said the heaviness from V-Lay away won't change the Z-height, or thickness, of the actual Ryzen CPU. That pretty much says AMD has done all it can to make true V-Cache-based Ryzen chips will work with the extant infrastructure of heat sinks and motherboards.

Samsung DDR5 registered module — DDR5 is happening the way and promises much higher capacity and much higher bandwidth too—and in all likelyhood—much higher initial prices besides.

Does this mean Zen 4 might come sooner?

Besides the V-Cache intelligence, AMD's Lisa Su unchangeable that the company's Zen 4 cores will be based on TSMC's 5nm process, which bequeath be delinquent sometime in 2022. Those hoping to see Zen 4 and its promise of DDR5 support sooner might flavour Lashkar-e-Tayyiba down, but memory transitions can be fraught with painful price hikes, too. If V-Cache connected an existing Zen 3-based platform can go toe-to-pointy-toed with Intel's CPUs, AMD give notice introduce Loony toons 4 with DDR5 when information technology's far more affordable than IT's likely to atomic number 4 when the original RAM is first released.

How will V-Cache and Zen 3 Ryzen compare with Intel's approaching Alder Lake?

This is rightfully the meg-junction transistor question we'll face as we close this year out: Will Intel's 10nm-based "big-little" design in Alder Lake put it back in black against AMD's Ryzen? If anyone tells you they know the answer, they're lying. We'll have to wait until we see Intel's Alder tree Lake parts and AMD's V-Cache-founded Ryzen before anyone can do this question.

When can I buy a Ryzen with V-Lay away?

There are no rocklike inside information on when you'll comprise able to buy a CPU with V-Hoard. Well-nig as close we can get is "production later this year," so we'd guess it'll get in ahead the vacation shopping season begins.