AMD Ryzen 3 3100 Review - Disrupting Price/Performance 15

AMD Ryzen 3 3100 Review - Disrupting Price/Performance

(15 Comments) »

Introduction

AMD Logo

Here's the cheapest AMD processor based on its fastest 7 nm "Zen 2" architecture, the Ryzen 3 3100. This is a chip of many firsts. It is the first to bring 4-cores and 8-threads under the $100-mark, the first with PCI-Express gen 4.0 in this segment, and one of the first with an unlocked multiplier (a distinction held by its compatriot, the Athlon 3000G). What's more surprising is that AMD did not disable any of its I/O features. You get the same I/O goodies as the $750 Ryzen 9 3950X! At its price of just $99, the Ryzen 3 3100 in this review goes right up against several Intel 9th Gen Core i3 and 10th Gen Pentium SKUs.

The Ryzen 3 3100 and Ryzen 3 3300X launching today are based on the same single-chiplet "Matisse" MCM as the rest of the 3rd generation Ryzen desktop processor series. This 4-core/8-thread processor ticks at 3.60 GHz with 3.90 GHz boost frequency, and supports the same high-frequency DDR4 memory modules as the rest of the series. You also get future-proofing in the form of PCI-Express gen 4.0, which you can use with motherboards based on the new B550 chipset or the premium X570 chipset. With a BIOS update, the processor is also compatible with older motherboards based on AMD 400-series chipsets.



AMD carved out the Ryzen 3 3100 by taking a single-chiplet "Matisse" processor, similar to a Ryzen 7 3800X, disabling two cores per CCX, and halving the L3 cache on both. It hence ends up as a quad-core part with a 2+2 CCX configuration. Each of the two cores per CCX has access to up to 8 MB of L3 cache. With 512 KB L2 cache per core and 16 MB of L3 cache, the caches add up to 18 MB "total cache." The Ryzen 3 3300X takes a slightly different approach, which you can read about in its review.

With prices of just $99 for the 3100 and $120 for the 3300X, AMD is hoping to woo the mainstream gaming crowd by letting them allocate more of their PC building budget to the graphics card. You'll need one, as unlike the Ryzen 3 3200G "Picasso," the Ryzen 3100 and 3300X lack integrated graphics. The processor's TDP is rated at 65 W.

We review the Ryzen 3 3100 in this article, comparing it with a broad spectrum of processors across our refreshed CPU bench.

AMD Ryzen 3 3000 Market Segment Analysis
 PriceCores /
Threads
Base
Clock
Max.
Boost
L3
Cache
TDPArchitectureProcessSocket
Athlon 3000G$502 / 43.5 GHzN/A4 MB35 WZen14 nmAM4
Athlon 200GE$552 / 43.2 GHzN/A4 MB35 WZen14 nmAM4
Ryzen 3 1200$604 / 43.1 GHz3.4 GHz8 MB65 WZen14 nmAM4
Core i3-9100F$754 / 43.6 GHz4.2 GHz6 MB65 WCoffee Lake14 nmLGA 1151
Athlon 240GE$802 / 43.5 GHzN/A4 MB35 WZen14 nmAM4
Ryzen 3 2200G$854 / 43.5 GHz3.7 GHz4 MB65 WZen14 nmAM4
Ryzen 3 3100$1004 / 83.6 GHz3.9 GHz16 MB65 WZen 27 nmAM4
Pentium G5600$1002 / 43.9 GHzN/A4 MB54 WCoffee Lake14 nmLGA 1151
Ryzen 5 1400$1054 / 83.2 GHz3.4 GHz8 MB65 WZen14 nmAM4
Ryzen 3 1300X$1154 / 43.4 GHz3.7 GHz8 MB65 WZen14 nmAM4
Ryzen 5 1600$1106 / 123.2 GHz3.6 GHz16 MB65 WZen14 nmAM4
Ryzen 3 3300X$1204 / 83.8 GHz4.3 GHz16 MB65 WZen 27 nmAM4
Ryzen 5 2600$1206 / 123.4 GHz3.9 GHz16 MB65 WZen12 nmAM4
Core i3-8300$1404 / 43.7 GHzN/A8 MB65 WCoffee Lake14 nmLGA 1151
Ryzen 5 1500X$1404 / 83.5 GHz3.7 GHz16 MB65 WZen14 nmAM4
Ryzen 5 2400G$1504 / 83.6 GHz3.9 GHz4 MB65 WZen14 nmAM4
Ryzen 5 1600X$1506 / 123.6 GHz4.0 GHz16 MB95 WZen14 nmAM4
Ryzen 5 2600X$1506 / 123.6 GHz4.2 GHz16 MB95 WZen12 nmAM4
Core i5-9400F$1606 / 62.9 GHz4.1 GHz9 MB65 WCoffee Lake14 nmLGA 1151
Ryzen 7 1700$1708 / 163.0 GHz3.7 GHz16 MB65 WZen14 nmAM4
Ryzen 7 1700X$1708 / 163.4 GHz3.8 GHz16 MB95 WZen14 nmAM4
Ryzen 5 3600$1756 / 123.8 GHz4.4 GHz32 MB65 WZen 27 nmAM4
Ryzen 7 2700$1708 / 163.2 GHz4.1 GHz16 MB65 WZen12 nmAM4
Core i5-8400$1906 / 62.8 GHz4.0 GHz9 MB65 WCoffee Lake14 nmLGA 1151
Ryzen 7 2700X$1958 / 163.7 GHz4.3 GHz16 MB105 WZen12 nmAM4
Core i3-8350K$1954 / 44.0 GHzN/A8 MB91 WCoffee Lake14 nmLGA 1151
Core i5-8600K$2506 / 63.6 GHz4.3 GHz9 MB95 WCoffee Lake14 nmLGA 1151
Core i5-9600K$2006 / 63.7 GHz4.6 GHz9 MB95 WCoffee Lake14 nmLGA 1151
Ryzen 5 3600X$2056 / 123.8 GHz4.4 GHz32 MB95 WZen 27 nmAM4

A Closer Look

Processor packaging front view
Processor packaging back view

The Ryzen 3 3100 ships in a simple paperboard box with a window that shows the processor inside. The Ryzen motif of the carbon fiber pattern backdrop hints at this being a 3rd generation Ryzen chip.

Processor bundled cooler front view
Processor bundled cooler back view

AMD includes a Wraith Stealth cooling solution with the Ryzen 3 3100. This is a noise-optimized cooler designed for chips with 65 W TDP.

Processor front view
Processor back view

The Ryzen 3 3100 processor looks like any conventional AMD processor with a large IHS dominating the top, and a 1,331-pin micro-PGA in the bottom. The "Zen 2" CCD chiplet is made in Taiwan, the I/O die in the US, and the two are put together at a facility in China.

Processor installed in motherboard

The Ryzen 3 3100 can be paired with a fairly big selection of AM4-compatible coolers that have been released since 2017.

Architecture

The architecture is no different from the Ryzen 9 3950X or any other "Matisse," so you can click on the button below to read about it, or skip that section if you're familiar with it.

AMD Zen 2 Microarchitecture Brief

The AMD Zen 2 Microarchitecture


AMD's 3rd generation Ryzen processors use the "Zen 2" microarchitecture. The 2nd generation Ryzen chips use an enhanced first-generation "Zen" derivative called "Zen+," which has process and boost algorithm improvements eke out roughly a 4% IPC uplift. With "Zen 2," AMD's key design goal is to finally beat Intel in the IPC game. IPC, or instructions per clock, is loosely used to denote a CPU core's performance at a given clock speed. For the past 15 or so years, Intel dominated AMD at IPC, while AMD attempted to make their processors competitive by cramming in more CPU cores than Intel at any given price point for competitive multi-threaded performance. Today's software environment is increasingly multi-threaded, as are games. With "Zen 2," AMD set itself an ambitious double-digit-percentage IPC uplift target to catch up or overtake Intel's latest "Coffee Lake" microarchitecture at IPC. AMD didn't stop there and even increased core counts for the platform at higher price points. The 3rd generation Ryzen family even includes a 16-core processor, which is a tremendous core count for the mainstream desktop platform.


Before we get into the interesting and quirky way AMD crammed 16 cores into this chip, let's talk about the "Zen 2" CPU core. After the colossal failure that was "Bulldozer," AMD set out to once again build strong and monolithic CPU cores that share nothing except L3 cache with other cores. It achieved this desired result with "Zen," which posted a mammoth 40%–50% IPC increase over "Bulldozer," catapulting AMD back into competitiveness. "Zen" cores IPC sits somewhere between "Haswell" and "Skylake/Coffee Lake," which was enough for AMD as it backed the IPC increase with higher core counts compared to Intel. Over the 8th and 9th generations of Core processors that retained the same IPC as "Skylake", Intel shored up core counts to match AMD. Wanting to set up a definitive edge over Intel, AMD not only worked to increase IPC, but also core counts.

The "Zen 2" CPU core has essentially the same component layout and hierarchy as "Zen," but with major changes and broadening of key components. As with "Zen" (or most x86 CPU cores), the "Zen 2" core is made up of five key components: Fetch, Decode, Integer, Floating-point, and Load/Store. Fetch and Decode tell the CPU core what needs to be done and what data or instructions are needed; Integer and Floating-point Unit execute a mathematical model of what needs to be done depending on the data type and nature of the instruction; Load/Store are the I/O of the CPU core. At various levels, there are tiny buffers, registers that store instructions, and larger caches that cushion data-transfers between various components.


AMD updated the Fetch and Decode units, which contribute to IPC, by making the CPU work "smarter." The updated Integer and FPU make the CPU work "harder," the Load/Store unit's job is to make sure the other components aren't starved for things to do. The Fetch unit is updated with a TAGE branch predictor. Invented in 2006, TAGE is considered the best branch-prediction technique by the IEEE. AMD broadened the BTB (branch target buffers) at L1 and L2 by doubling the L1 entries to 512k, and L2 entries to 7,000 from 4,000. The ITA (indirect target array) has also been expanded. The design goal for updating the Fetch unit is to lower "mispredictions" (bad guesses) that wasted load/storage operations by 30 percent. The 32 KB L1 instruction cache has also been improved. The Decode unit has two improvements to the Op cache: improved instruction fusion and the ability to push up to 4,000 fused instructions per clock cycle.


We now move on to the two components that contribute the most to the IPC, the Integer and Floating-point Units. The Integer unit receives incremental updates in the form of a broader integer scheduler that handles 92 entries (up from 84), with four 16-entry ALU queues and one 28-entry AGU queue. The general-purpose physical register file has now been expanded to 180 entries from 168. The issue-per-cycle has been broadened to 7 from 6, which now includes 4 ALUs and 3 AGUs. The reorder-buffer (ROB) has been broadened to 224 entries, up from 192. The SMT (simultaneous multi-threading) logic has been tweaked to better share the ALUs and AGUs among the logical processors. The FPU has the bulk of the innovation with "Zen 2." The load/store bandwidth of the FPU has been doubled to 256-bit, up from 128-bit on "Zen."

The core now also supports a sort of AVX-256: AVX/AVX2-flagged instructions with 256-bit registers. There are many applications for this, such as physics simulation, audio-stack execution, and memory-copy performance improvement. Multiplication operation latency has been improved by 33 percent.


Lastly, we have the Load/Store unit with a similar round of generational enhancements. The entry-store queue is expanded to 48 entries, up from 44. The L2 TLB (translation lookaside buffer) has been expanded by 33% to 2,000 entries, and its latency improved. The 32 KB L1 Data cache has two 256-bit read paths and one 256-bit write path, with 64-byte load and 32-byte store alignment boundaries. The load/store bandwidth to L2 has been doubled to 32 bytes per clock.


We now move on to the cache hierarchy, which is essentially the same as "Zen." Notwithstanding the technical changes described above, the "Zen 2" core still has a 32 KB 8-way L1I cache, a 32 KB 8-way L1D cache, and a dedicated 512 KB 8-way L2 cache. AMD doubled the shared L3 cache size to 16 MB. Every CCX (quad-core compute complex) on a "Zen 2" processor now has 16 MB of shared L3 cache. The doubling in L3 cache size was necessitated not just by Intel sharing larger amounts of L3 cache among individual cores on the "Coffee Lake Refresh" silicon (16 MB shared among all 8 cores), but also because the larger L3 cache on a "Zen 2" CCX cushions data transfers with the I/O controller die.


This brings us to the interesting and quirky way AMD achieved 16 cores. The Ryzen 9 3900X and Ryzen 5 3600 processor packages are codenamed "Matisse." This is a multi-chip module (MCM) of one or two 7 nm 8-core "Zen 2" CPU chiplets and one I/O controller die built on the 12 nm process. AMD made sure only those components that tangibly benefit from the shrink to 7 nm—namely, the CPU cores—are built on the new process, while those components that don't benefit from 7 nm stay on the existing 12 nm process, on the I/O controller die. AMD carved the Ryzen 5 3600 out by using just one "Zen 2" chiplet and enabling 6 cores on it, 3 per CCX.


These components include the processor's dual-channel DDR4 memory controller, a 24-lane PCI-Express gen 4.0 root-complex, and an integrated southbridge that puts out some platform connectivity directly from the AM4 socket, such as SATA 6 Gbps and USB 3.1 ports. Infinity Fabric is the interconnect that binds the three dies by providing a 100 GB/s data path between each CPU chiplet and the I/O controller. The memory clock is now practically de-coupled from the Infinity Fabric clock, which should improve memory overclocking headroom. AMD also claims to have put a lot of work into improving memory-module compatibility across brands, especially since Samsung stopped mass-production of the expensive B-die DRAM chip that favored AMD processors. The memory scaling article talks a little more about this.

Architectural Innovations Specific to Ryzen 3 3300X and 3100

Both the Ryzen 3 3300X and Ryzen 3 3100 are 4-core/8-thread parts, but their segmentation goes beyond clock speeds to justify the 20% price gap between them. AMD tapped into the multi-core topology of its "Zen 2" microarchitecture to obtain the 4-core configuration differently between the two SKUs. Each 7 nm "Zen 2" chiplet (CCD) physically features eight CPU cores spread across two CCX (compute complexes) with four cores and 16 MB of L3 cache, each. For the 8-core Ryzen 7 parts, all eight cores are enabled. For the 6-core Ryzen 5 and 12-core dual-chiplet Ryzen 9 3900X, one core per CCX is disabled, yielding a 3+3 core CCX configuration.


The Ryzen 3 3300X and 3100 are designed differently at the CCX-level. For the entry-level 3100, AMD disabled two cores per CCX and reduced the L3 cache amount to 8 MB per CCX. This 2+2 core CCX configuration with 16 MB of L3 cache (2x 8 MB) still qualifies AMD's specs sheet. The 3300X has a key difference. One of the two CCX on the chiplet is completely disabled, and all four cores are localized to a single CCX, with its full 16 MB L3 cache enabled and shared between all four cores. This improves inter-core latency and lets a core access >8 MB of L3 cache if it wants. For the Ryzen 3 3100, inter-core communication between CCXs comes with certain performance costs arising from latency.

AMD B550 Chipset

With premium AMD X570 chipset-based motherboards starting at $150, it's less likely that someone would pair the 3rd gen Ryzen 3 with it. Choosing a cheaper B450 motherboard would mean giving up on killer features such as PCIe gen 4.0. AMD hence launched the new B550 mid-range chipset alongside these processors. Motherboards based on the new chipset are expected to be available around mid June, 2020, at starting prices similar to B450-based ones. The B550 chipset lets you have PCI-Express gen 4.0 connectivity from the "Matisse" processor, while limiting general purpose PCIe downstream connectivity to gen 3.0.


On a typical B550 chipset motherboard, the main PCI-Express x16 slot will be gen 4.0 if paired with a 3rd gen Ryzen "Matisse" processor, as would one of the board's M.2 NVMe slots that's wired to the processor. All other PCIe or M.2 slots which are wired to the B550 chipset will be gen 3.0. This way, future-proofing of the platform for next-generation graphics cards and SSDs remains intact. The B550 chipset provides up to six SATA 6 Gbps ports with AHCI and RAID capability, up to two 10 Gbps USB 3.1 gen 2 ports (in addition to four such ports put out by the "Matisse" processor), two additional USB 3.1 gen 1 ports, and six USB 2.0 ports. The platform's HDA and LPCIO buses are located on the processor.


A word on compatibility: the B550 chipset only supports 3rd gen Ryzen "Matisse" processors as of this writing and AMD confirmed support for next-generation processors based on the "Zen 3" architecture. You cannot pair a B550 motherboard with older Ryzen 2000/1000 processors or even the 3200G or 3400G APUs based on the older "Zen+" microarchitecture. There will be clear labeling on B550 chipset motherboard boxes to this effect.

What we like most about the B550 is its low TDP, which lets motherboard designers make do with passive heatsinks; unlike X570, which requires active fan-heatsinks.
Our Patreon Silver Supporters can read articles in single-page format.
Discuss(15 Comments)