Question vega vs RDNA2 iGPUs

Rannar

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Aug 12, 2015
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after reading some reviews (not good deepdives yet unfortunately) it seems RDNA2 is ca 80%-100% faster on average compared to old outgoing Vega 8 but in some cases it-s much more than that.

Horizon Zero Dawn 17 vs 41 fps avg 1080p low for example. What does vega choke on in those type of games?

Is it 8 ROP-s vs 16/ one shader engine vs 2, DDR4 vs DDR5, difference of CU-s or just a combination of all of those?
on paper RDNA2 has ca 60-90% higher tflops, ca 50% more mem bandwith combined with 175% higher fillrate and who knows how much higher geometry rate?

i have 4800H laptop with iGPU only and have noticed resolution scaling does not give as much benefit as it should in many games specially newer ones so there are some other bottlenecks (geometry which does not really scale between resolutions?)
 

maddie

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Jul 18, 2010
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after reading some reviews (not good deepdives yet unfortunately) it seems RDNA2 is ca 80%-100% faster on average compared to old outgoing Vega 8 but in some cases it-s much more than that.

Horizon Zero Dawn 17 vs 41 fps avg 1080p low for example. What does vega choke on in those type of games?

Is it 8 ROP-s vs 16/ one shader engine vs 2, DDR4 vs DDR5, difference of CU-s or just a combination of all of those?
on paper RDNA2 has ca 60-90% higher tflops, ca 50% more mem bandwith combined with 175% higher fillrate and who knows how much higher geometry rate?

i have 4800H laptop with iGPU only and have noticed resolution scaling does not give as much benefit as it should in many games specially newer ones so there are some other bottlenecks (geometry which does not really scale between resolutions?)
I think you might really mean Cezanne vs Rembrandt, not, Vega vs RDNA2. Not the same thing.
 
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Rannar

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Aug 12, 2015
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I think you might really mean Cezanne vs Rembrandt, not, Vega vs RDNA2. Not the same thing.
no i ment vega vs RDNA2
cezanne and rembrandt have both zen3 cores so CPU perf is very similar. without discreete GPU its gaming perf is totally limited by iGPU.
 

Leeea

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Apr 3, 2020
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When you say Vega, most people think you are referring to the Vega series of AMD graphics cards that use expensive HBM memory:
Vega56 - I own one, most popular
Vega64
Radeon 7 - miners dream

The Vega series was a nice card, but RDNA2 is just better. Pretty much in every way.

Vega is based off of the last/fifth generation of GCN, which while mature was also outdated. Performance of Vega would improve over time as Directx12 rolled out. However AMD would release RDNA next as it would better reflect how games were looking to utilize the GPU. RDNA however had issues, and RDNA2 fixes those issues.


Market reception of the Vega series was lukewarm at the time. In 2022 these cards are far better received then 2017. On release they were inferior to the GTX 10 series. Directx12_1 support and performance in Vega ended up being rather good however, and combined with the graphics card shortage would redeem these cards in what is sometimes referred to as an AMD "fine wine" effect.


As of writing this post, many people would be delighted to have a Vega series GPU. A Vega 56 is similar in performance to a RTX3050 these days. Four years later and it is still a compelling platform.
 
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Leeea

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no i ment vega vs RDNA2
cezanne and rembrandt have both zen3 cores so CPU perf is very similar. without discreete GPU its gaming perf is totally limited by iGPU.
When it comes to iGPUs, Vega was dramatically better then its competitors. But Vega was also designed for HBM memory, which an iGPU is the opposite of. In my opinion Vega was not ideal for an iGPU, but it still blew the competition ( Intel's iGPUs ) out of the water. Comes with superior driver support to boot.

RDNA was designed for cheaper less exotic memory from the start. In my opinion RDNA2 is a better fit for an iGPU and will provide more consistent performance. But RDNA2 is just now starting to appear in iGPUs, and the previous gen Vega iGPUs are still better then their competitors*.


*Vega8 showing it is still better then Intel's latest and greatest UHD770, dated March 7th 2022:
at 1/2 the cost also, impressive for what is a GCN5 architecture first released in 2017.
 
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GodisanAtheist

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It bums me out that RDNA2 IGPs aren't shipping with any IC, it seems like exactly the use case scenario where IC would make the biggest impact: the terrible DDR4/5 bandwidth IGPs have to deal with.

Maybe one day we'll get a sort of dynamic allocation IC that can be used by both the CPU and IGP so cache isn't sitting "idle" in the event the IGP isn't getting much use.
 

Mopetar

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Jan 31, 2011
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The cache would use up too much real estate for what's supposed to be a more budget-oriented part. It really just comes down to transistor budget at the end of the day and apparently the extra hardware resources or the smaller die size are worth more.

I do suspect that eventually we might see a unified cache that both the CPU and GPU can draw from. Depending on how AMD designs it all it could even be something that could benefit from stacked V-cache which could allow for some premium APUs.
 

ryanjagtap

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Sep 25, 2021
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I do suspect that eventually we might see a unified cache that both the CPU and GPU can draw from. Depending on how AMD designs it all it could even be something that could benefit from stacked V-cache which could allow for some premium APUs.
This. The video of How it's Built: AMD 3D V-cache at the last part at 09:13 Robert says that they can stack GPU as well, so that unified cache idea looks promising. But we're already seeing igpu on IO die for zen 4 so I don't know if they would design such APUs. (Not to mention the thermal problem with having GPU stacked on cache or on the core)
 

Shivansps

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Sep 11, 2013
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Vega (and polaris), is not very bandwidth efficient, so the Vega APU are working with what they have, and performance will vary from title to title depending on how much bandwidth they need for that specific load, and not only for gpu tasks, but for CPU tasks as well.

This is why you have some cases were a 5700G is below RX550 and others were it beats the RX550 by a large margin.

RDNA2 apus are going to have the same problem when compared to a dgpu like the RX6500XT.
 
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