I will be honest, after AMD did not update its FX processor line using the Steamroller architecture, I was not too hopeful for the brand to see anything new in 2014. But since the start of the year the 5 GHz turbo FX-9590 has been rereleased as a consumer part and today AMD is showing it can get four Piledriver modules down to 95W with a few frequency adjustments and cherry picking the dies. This is accompanied with price cuts for the eight-thread FX parts, which AMD is aiming squarely at similarly priced Intel i5 and i3 processors.

The Information

The new CPUs being released today come in three flavors. The FX-8370 is an upgraded version of the FX-8350, giving an extra bump in clock speeds over the FX-8350 in the same 125W envelope. The other two processors, the FX-8370E and FX-8320E, carry this new ‘E’ designation from AMD, representing their ‘energy efficient’ range. For these processors, this means a four-module die with 8 threads with turbo frequencies matching their non-E counterparts but base frequencies reduced slightly.

Part of this makes you wonder just how much energy is used per MHz to hit the high numbers. It only takes a relatively small drop in base frequency to net a large power gain. We saw similar things from AMD with their 65W configurable TDP Kaveri parts earlier this year.

The base frequency drop does come across as a larger number than a first glance might suggest. The FX-8370E is 700 MHz lower than the FX-8370, while the FX-8320E is only 300 MHz lower. While I can imagine that 700 MHz reduces the power consumption by 30W, the 300 MHz number might indicate a better binned CPU from AMD. One of the issues AMD will have however is the Turbo mode. In the past, only specific workloads seem to cause the low thread count/high frequencies to kick in, meaning that an abnormal workload will keep the frequency low.

Also, unlike on Intel’s side of the fence, the motherboard manufacturers have not embraced MultiCore Turbo on AMD with the same gusto. This is a feature that places all the cores of the CPU in its highest frequency state any time it is not idle in order to allow software to be completed faster at the expense of power consumption and some heat. While this does not affect our testing due to the way we test, it might affect the experience the user has on a day-to-day level by being down on the top turbo mode.

In terms of the processor architecture, one of the most obvious questions to ask is:

Why update the FX line with more Vishera based processors? Can’t we get an update?

AMD’s reasoning for these new processors, apart from the slowly increasing yields of the higher bin parts over the past year and tweaking the overall design, is because of the motherboards available on the market. Due to the construction of some of the early motherboards intended for AMD’s no-IGP line, these early motherboards could only support 95W or 125W maximum, let alone the 220W of the FX-9590/9370 behemoths. By releasing an 8-thread Vishera processor with a 95W TDP, this allows these users to upgrade without spending an extra $120-$200 on a new motherboard.

With our CPU sample from AMD, we were also sent one of the newest motherboards that shows this limitation. We ran a news item on the 990FX Killer when it was first announced, and it was interesting due to its use of M.2 on 990FX. One of the items I spotted at the time on the specifications sheet was its recommended limit of processors: 125W TDP maximum. At the time (December 2013) AMD’s Roy Taylor and I discussed this on Twitter. It seemed odd that new motherboards were coming out that would not support AMD’s fastest CPU, even though motherboard manufacturers and AMD’s partners wanted to push the FX-9590 as the top end product. To solve that conundrum, this line of E processors was launched.

At the moment, AMD’s future roadmaps do not include FX processors based on new architectures, and there is no publicly disclosed new chipset, as we discussed in our recent FX-9590 review.

However, during the pre-briefings for these processors with AMD, one series of lines from AMD’s Adam Kozak piqued my interest, regarding the future of the FX processor line. Particularly mentioned was the lack of further FX updates for the rest of 2014, however there were indications that 2015 might hold something. AMD’s James Prior answered an email of mine regarding the exact wording, and aside from confirming that AMD are committed to supporting the current AM3+ lineup, one line gives hope:

“The AMD of today is funding the AMD of tomorrow by working hard to ensure the ongoing success of products like FX.”

To say ‘today funds tomorrow’ is no big leap of the imagination, but ‘ongoing success’ could stress future updates for the FX line. Now that AMD has started this energy efficient nomenclature, it would make sense to sustain it and introduce it to more of its customers over time. The earliest indication is 2015 for anything slightly new, though it is currently difficult to predict exactly what would be coming. But if we take into context 'products like FX', it might imply that there are no future FX parts, or at least how we commonly recognize them.

But for now we have the energy efficient side of Vishera to test.

The CPU, The Chipset and The DRAM

While AMD is stating that the 32nm process for Vishera has been updated and tweaked over time to allow for better yields and more efficient products, they have not stated if the silicon is changed in any way. For all intents and purposes, 32nm is getting a bit long in the tooth in the land of processors – Intel’s 14nm designs and second generation tri-gate transistors/FinFETs are almost upon us and 32nm is some way behind.

CPU Specification Comparison
CPU Manufacturing Process Cores GPU Transistor Count (Schematic) Die Size
Intel Haswell-E
22nm 8 N/A 2.6B 356mm2
Intel Haswell
GT2 4C
22nm 4 GT2 1.4B 177mm2
Intel Haswell
22nm 2 GT3 1.3B 181mm2
Intel Ivy Bridge-E
22nm 6 N/A 1.86B 257mm2
Intel Ivy Bridge
22nm 4 GT2 1.2B 160mm2
Intel Sandy Bridge- E 6C 32nm 6 N/A 2.27B 435mm2
Intel Sandy Bridge 4C 32nm 4 GT2 995M 216mm2
Intel Lynnfield
45nm 4 N/A 774M 296mm2
AMD Trinity
32nm 4 7660D 1.303B 246mm2
AMD Vishera
32nm 8 N/A 1.2B 315mm2

AMD is keeping the new energy efficient CPUs in the AM3+ socket, which means the 990FX is still top of the chain. However, these new CPUs are aimed at the lower end motherboards or even the older chipsets that were not designed to cope with >95W TDPs. In AMD’s briefing, they specifically called out the 700 series that supported AM3 and DDR3, although this applies to 800 series and 900 series equally.

The 990FX+SB950 platform combination is still limited to PCIe 2.0 without using a PCIe 3.0 PLX chip, although the connection to the CPU in that orientation is still PCIe 2.0 - only the data between the GPUs is accelerated. Nevertheless this is still the latest platform from AMD to have SLI support, with the north bridge being able to use two PCIe 2.0 x16 slots. The south bridge gives out the IO, to which we get six SATA 6 Gbps ports that are RAID capable. No native USB 3.0 though, as this combination was introduced before USB 3.0 became a must-have feature. This is one of the common criticisms with AM3+ - it needs a chipset update. There are plenty of PCIe 2.0 x1 ports in order to use USB 3.0 controllers, however this adds cost and AMD motherboards are generally low cost to begin with. It also goes against the mantra AMD is using for the new energy efficient CPUs of keeping the motherboard.

Memory is still DDR3, with the new CPUs natively supporting DDR3-1866 MHz under JEDEC specifications. Nevertheless, in AMD’s pre-brief it was stated that DDR3-2133 overclocking should be possible on almost all samples, with DDR3-2400 being a potential. Normal rules apply with DDR3: if you are buying new, buy a single kit with all the modules you need rather than two kits of the same modules. A kit is by definition only designed to work with itself, and it may be too strict on its timings to work with another kit, even if that kit is the same type. That is why four module kits often have a lower specification than a dual module kit. If the kit cannot combine with another kit at the rated settings, it can be a hard problem to diagnose. However the DDR3 market is quite mature at this stage, with plenty of options available.

Competition and Market

There are many ways in which a manufacturer can order up the competition. We could have 8-thread CPUs against 8-thread CPUs, or we could put 95W CPUs against 95W CPUs. For these processors, due to the accompanied price reduction across most of the FX desktop line, AMD is deciding to compare setups based on price.

This slide AMD provided is rather amusing. It shows that an FX-8320E + R9 280X will perform similarly to an i5-4430 + GTX 770 while being $88 cheaper. This is despite the DOTA 2 benchmark being performed on a UHD monitor which would cost just as much. But then again, perhaps that extra $80 could be going on an SSD – AMD’s focus over the past few years has always been oriented towards the cost effectiveness.

In real terms, the FX-8370 sits between the FX-8350 and the FX-9370, and the FX-8370E/FX-8320E are both equally priced to their non-E counterparts. The tradeoff is that for the lower TDP option, you pay a bit more compared to if we just looked at the speed. 

AMD FX CPU Comparison
Release Date 04-
10-2012 09-
10-2012 10- 2012 09-
07- 2013 07- 2013
Modules 2 3 4
L1 Cache (Code) 128 KB 192 KB 256 KB
L1 Cache (Data) 64 KB 96 KB 128 KB
L2 Cache 4 MB 6 MB 8 MB
L3 Cache 8 MB
TDP 125W 95W 125W 95W 125W 220 W
Base Frequency 4200 3900 3200 3500 4000 3300 4000 4400 4700
Turbo Frequency 4300 4200 4000 4000 4200 4300 4300 4700 5000
Core Name Vishera
Microarchitecture Piledriver
Socket AM3+
Memory Support DDR3-1866
Price $140 $140 $147 $147 $180 $200 $200 $211 $230

Unfortunately AMD’s pricing is not telling the whole story. For the FX-9370 and FX-9590, that pricing is for the CPU-only version, whereas the FX-8370 and below pricing includes a boxed cooler. AMD’s reasoning on this is that for users buying the 9000 series, even with the price cuts, many of them will either purchase the version with the all-in-one liquid cooler (+$80 or so), or use their own after-market cooling in order to deal with the 220W TDP.

If we do a direct comparison of the SEP of the new CPUs with prices at retail for Intel Haswell:

SEP vs Retail
CPU TDP Threads US Price
Core i5-4690K 88W 4 $240
FX-9590 220W 8 $230
Core i5-4690 84W 4 $225
Core i5-4670K 84W 4 $220
FX-9370 220W 8 $211
Core i5-4590S 65W 4 $200
Core i5-4590 84W 4 $200
FX-8370 125W 8 $200
FX-8370E 95W 8 $200
Core i5-4460 84W 4 $190
Core i5-4430 84W 4 $190
FX-8350 125W 8 $180
Core i3-4370 54W 4 $160
FX-8320 125W 8 $147
FX-8320E 95W 8 $147
Core i3-4350 54W 4 $145

At the high end, the FX-9590 has competition with the i5-4670K although with twice as many threads in tow. At the FX-8370 level, the pricing of both the Core i5-4590 and the S model would make for an interesting battle if we had these CPUs in to test. For the FX-8320E, we are split between two Core i3s, meaning that the i3 with two cores and HyperThreading is up against a full 8 threads from the FX-8320E. While this seems one sided, the i3’s power consumption is almost half that of the FX processor. AMD is also keen to point out that all of its CPUs are unlocked for overclocking, unlike the competition where it is limited.

This Review

At this point in time AMD is currently only sampling the FX-8370E to the press, with the other CPUs to follow later this month. Due to our sample arriving only yesterday, this aims to be a quick overview of performance against other processors we have already tested. Note we only have a few from the list above, but as the new processors arrive we can aim for a more targeted punch-counterpunch scenario with overclocked testing. Our testing today encompasses the usual array of CPU and gaming benchmarks at stock speeds and official supported memory frequencies. 

Test Setup

Processor AMD FX-8370E 4M/8T 3.3 GHz / 4.3 GHz
Motherboard ASRock 990FX Extreme9
Cooling Corsair H80i
Cooler Master Nepton 140XL
Power Supply OCZ 1250W Gold ZX Series 
Corsair AX1200i Platinum PSU
80 PLUS Gold
80 PLUS Platinum
Memory G.Skill 2x4 GB DDR3-1866 8-9-9 1.5V
Memory Settings XMP
Video Cards MSI GTX 770 Lightning 2GB (1150/1202 Boost)
Video Drivers NVIDIA Drivers 337.88
Hard Drive OCZ Vertex 3
Optical Drive LG GH22NS50
Case Open Test Bed
Operating System Windows 7 64-bit SP1
USB 2/3 Testing OCZ Vertex 3 240GB with SATA->USB Adaptor

Many thanks to...

We must thank the following companies for kindly providing hardware for our test bed:

Thank you to OCZ for providing us with PSUs and SSDs.
Thank you to G.Skill for providing us with memory.
Thank you to Corsair for providing us with an AX1200i PSU and a Corsair H80i CLC.
Thank you to MSI for providing us with the NVIDIA GTX 770 Lightning GPUs.
Thank you to Rosewill for providing us with PSUs and RK-9100 keyboards.
Thank you to ASRock for providing us with some IO testing kit.
Thank you to Cooler Master for providing us with Nepton 140XL CLCs.

Load Delta Power Consumption

Power consumption was tested on the system while in a single MSI GTX 770 Lightning GPU configuration with a wall meter connected to the OCZ 1250W power supply. This power supply is Gold rated, and as I am in the UK on a 230-240 V supply, leads to ~75% efficiency under 50W and 90%+ efficiency at 250W, suitable for both idle and multi-GPU loading. This method of power reading allows us to compare the power management of the UEFI and the board to supply components with power under load, and includes typical PSU losses due to efficiency.

We take the power delta difference between idle and load as our tested value, giving an indication of the power increase from the CPU when placed under stress. 

Power Consumption Delta: Idle to AVX

I retested our very early FX-8150/FX-8350 samples again for the power tests due to lack of data, and even though the result was very high over several tries it was consistent. Thus the power saving by comparison, switching to the efficient processors is great, but the latest AMD architectures perform best.

CPU Benchmarks
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  • just4U - Tuesday, September 2, 2014 - link

    I noticed with cpu-z that power is all over the place. so yeah.. but still..
  • Death666Angel - Tuesday, September 2, 2014 - link

    "e.g., my 4790K at 4.4 GHz on all the cores at 1.225 V consumes around 115 W"
    So you are running the CPU out of spec but expect it to be in spec in other areas? If you OC, you increase the TDP! Don't OC and it will stay very much within its TDP limit.
  • just4U - Tuesday, September 2, 2014 - link

    4.4GHZ is turbo boost on the 4790K. It runs at that speed out of the box.
  • Akrovah - Tuesday, September 2, 2014 - link

    Only on a single core. He specified 4.4 Ghz on all cores. hence the assumption of overclocking.
  • TiGr1982 - Tuesday, September 2, 2014 - link

    The Turbo for all the cores loaded is officially 4.2 for 4790K. However, even at 4.2 it won't stay in its 88 W, unless you are lucky to get a very good CPU instance in order to undervolt it enough and still maintain stability - just look all the reviews of 4790K - it consumes quite a bit more power than 4770(K) under heavy CPU load, despite the formal 4 W (88 W vs 84 W) TDP difference. I haven't finished my tuning yet, but anyway, obviously, going from 4.2 to 4.4 at the same voltage won't increase TDP from 88 W to 115 W.
  • Flunk - Tuesday, September 2, 2014 - link

    Thermal Design Power is the amount of power that the chip is supposed to generate, not power used. Also, how are measuring power consumption? There are a lot of factors involved and its difficult to isolate just the CPU.
  • techguyz - Thursday, September 4, 2014 - link

    And do you think a 95w AMD CPU uses just 95w? Nope.
  • TiGr1982 - Tuesday, September 2, 2014 - link

    No, these Piledriver-based FXes are just 2 years old, not 3 :)
    These were first released back in October 2012.
  • silverblue - Tuesday, September 2, 2014 - link

    They're Bulldozer done better, though not quite right, so you can perhaps forgive the "3 years old now" comment; still, I'd really like to see detailed power consumption figures especially when compared to the FX-8150, just to see how far they've actually come in that area.
  • TiGr1982 - Tuesday, September 2, 2014 - link

    Yes, if you add up initial Bulldozer FX-8150, OR-B2 ("Orochi B2") and the likes, then it happens to be 3 years, I agree, because these Piledriver FXes are just OR-C0 ("Orochi C0)".

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