Samsung DDR4 8Gb B-die timing guidelines for Ryzen

Viable for 3600-4000Mbps but skewed towards 3800Mbps with 1.4-1.65V depending on RAM chip quality. With GDM enabled. 

Note that most Ryzen 3000/5000 CPUs will not do more than 1900FCLK stable. 

Also Keep in mind that B-die is the least consistent DDR4 IC that I'm aware of. Unbinned/OEM B-die and low XMP spec B-die like 3200 16-18... can often struggle to scale to even 1.45V while being extremely temperature sensitive and doing horrific tCL tRCDRD and tRP. Like 3600 18-18-18 at 1.4V levels of horrific. On the flip side it is still B-die and so subtimings like tRFC can still go low.

tCL: 14-18 (can't be odd with GDM turned on)
tRCDWR: 8-18 (8 works most of the time but this also doesn't affect performance much)
tRCDRD: 13-18 (most good kits max out at 15)
tRP: 11-18 (low tRP is more important than low tRAS)
tRAS: 24-32 (just set it so that tRAS + tRP = tRC)

tRC: 38-50 (around 40 should work as long as your RAM doesn't suck)
tRRD_S: 4 (it always does 4)
tRRD_L: 4-6 (weaker dimms might need 6 to be stable)
tFAW: 16 (this always works)
tWTR_S: 3-5 (4 works most of the time. With a lot of voltage some sticks can do 3)
tWTR_L: 7-10 (8 works most of the time. With a lot of voltage some sticks can do 7)
tWR: 10-12 (I'd be very surprised if 10 doesn't work for you)
tRFC: 220-330 (I usually just use 280)
tCWL: equal to tCL or tCL-2 (no point pushing this lower as it will just raise your RDWR and WRRD timings if you do)
tRTP: 6-12 (8 works on most good kits)

tRDRDSCL: 2-4 (2 works most of the time)
tWRWRSCL: 2-4 (2 works most of the time)
tRDWR: just leave this on auto
tWRRD: just leave this on auto too
tRDRDSC: 1 (auto = 1)
tRDRDSD: 4 (only applies to multi rank setups)
tRDRDDD: 4 (only applies to multi rank setups)
tWRWRSC: 1
tWRWRSD: 6 (only applies to multi rank setups)
tWRWRDD: 6  (only applies to multi rank setups)
tCKE: 1 (ALWAYS WORKS)

If you're very lazy and your kit has a 3200 14-14 or better XMP I'd be very surprised if the following settings don't work for you. Also they aren't gonna be much slower than some hyper optimized 3800 C14 settings. 

FCLK: 1866
MCLK: 3733
VDIMM: 1.45 (I recommend a fan pointed at the RAM)
VSOC: 1.1V
GDM: Enabled

tCL: 16
tRCDWR: 16
tRCDRD: 16
tRP: 16
tRAS: 28

tRC: 44
tRRD_S: 4
tRRD_L: 6
tFAW: 16
tWTR_S: 4
tWTR_L: 8
tWR: 10
tRFC: 300

tRDRDCL: 2
tWRWRSCL: 2
tCWL: 16
tRTP: 8
tRDWR: AUTO
tWRRD: AUTO
tRDRDSC: 1
tRDRDSD: 4
tRDRDDD: 4
tWRWRSC: 1
tWRWRSD: 6
tWRWRDD: 6
tCKE: 1

this last set of timings is pretty much what I think a B-die "XMP" should/could look like if XMP was able to hold the all the settings.