Inwiefern unterscheidet sich das A0 PCB von den anderen?
Musstest du irgendetwas besonderes einstellen damit 4400 1T laufen? bekomme nicht mal 4133 1T zum Laufen
PCBs
Memory PCB can affect overclocking characteristics and compatibility. Presented here is a list of standard PCB layouts and what is known about them.
Please note: there is a lot of confusion about what is A0 and what is A1, with a lot of people incorrectly referring to A0 PCBs as A1. Keep in mind that PCB information reported in thaiphoon burner or other SPD reporting tools may not be accurate as it relies on the SPD being programmed correctly.
Single Rank (single-sided) with standard ICs
A0
A0 is the original single rank layout designed for JEDEC (stock) speeds up to DDR4-2133. It can be identified by having 8 normal ICs on one side that are rougly evenly spaced, with the SPD chip right in the middle if you're peeking under a heatspreader from the contacts side.
A0 PCB is also known as the "non-RGB PCB" as it's used on G.Skill non-RGB single rank kits up to DDR4-4266 (and older, now-discontinued non-RGB 4266+ kits). People often mistakenly call this PCB "A1", to the point that if you see an overclocker talk about "A1 PCB" they probably mean A0.
This is the best PCB for running extreme b-die profiles/presets aimed at 4000-4133 12-12-12 or 12-11-11. Not because it's a better PCB, but because it has better compatibility with 2-DIMM boards.
A1
A1 is designed for JEDEC (stock) speeds up to DDR4-2400, and is shared with the ECC D1 PCB. This means that on non-ECC modules you will see an empty pad for a 9th IC. This is normal and part of the design; it does not mean the PCB is being used improperly.
Compatibility is a bit of an unknown as vendors popular with overclockers don't use this PCB, but it has been tested with 4Gbit Samsung E-die from OEM kits and Crucial Ballistix and is certainly capable of at least DDR4-4266 CL19.
Identifying A1 vs A2
A1 looks similar to A2 under the heatspreaders - the ICs are in two groups, one on each side. There are a few 'tells';
A1 has the SPD chip on the front, next to an IC, and no components on the back. A2 has the SPD chip and some smd components on the back.
Both A1 and A2 have a single SMD capacitor by the notch. On A1 the edge of this is pretty much lined up with the edge of the notch, on A2 it's offset by a good 1-2mm.
A1 has unpopulated pads for SMD conponents supporting the 9th IC along the bottom edge that may be visible between the heatspreader and contacts.
A2
A2, also known as the "RGB PCB" as G.Skill use it on their RGB kits as well as more recent (at time of writing - early May 2019) non-RGB >4266 kits, is the latest (as of early May 2019) standard single rank PCB layout and is targeted at JEDEC (stock) speeds up to DDR4-2666. It's a very good PCB that's sadly best known for compatibility issues with 2-DIMM socket 1151 boards, especially the Asus Apex series - on which it needs CL of 19 or above for DDR4-3866+.
It should be stressed that problems doing tight timings on the A2 PCB are about compatibility not quality - on 4-DIMM socket 1151 boards it works great. If you're trying to do really extreme settings on A2-based b-die and having trouble, making sure XMP is enabled will often alleviate the problems. You should also look for a more recent bios that may improve compatibility.
A2 is identifiable by having all the ICs crammed tightly into two clusters, one on each side. The gap between the clusters is huge - about as big as the width of a cluster. If you're not sure which single rank 8-chip PCB you have, check the section above on A1 vs A2.