GDDR7 changes the VRAM rules.

GDDR7 spec basics

GDDR7 is the JEDEC standard that replaces GDDR6 and GDDR6X across consumer GPUs. The headline numbers are simple: 32 Gbps per pin at launch, with the roadmap pushing toward 36 Gbps and a 40 Gbps "extreme" tier that vendors are already sampling internally.

Module density matters more than people realise. GDDR7 launching with 16 Gb (2GB) modules — and 24 Gb (3GB) and 32 Gb (4GB) modules in the pipeline — means future cards can hit higher VRAM capacities without doubling the bus width. A 192-bit bus paired with 3GB modules gives you 18GB. That capacity flexibility is partly why NVIDIA can ship narrower-bus mid-range cards without the 8GB problem they had on the 4060.

PAM3 vs PAM4 — why signalling matters

Here's where GDDR7 gets technically interesting. GDDR6X used PAM4 (4-level pulse amplitude modulation) — encoding two bits per signal transition by switching between four voltage levels. Smart in theory, painful in practice: PAM4 needed tight signal-integrity margins, ran hot, and was Micron-exclusive (Samsung and SK Hynix never licensed it).

GDDR7 uses PAM3 instead — three voltage levels encoding roughly 1.5 bits per transition. It's a compromise: less raw theoretical bandwidth per cycle than PAM4, but dramatically better signal integrity, lower power per bit, and easier PCB routing for board partners.

The win shows up in three places:

• Signal integrity at 32 Gbps is achievable on standard 8-layer board designs — PAM4 needed expensive 10-12 layer PCBs at 21 Gbps.
• Power per bit is roughly 30% lower than PAM4 at equivalent speeds — the entire memory subsystem runs cooler.
• All three major DRAM suppliers ship PAM3 — competitive supply rather than the Micron monopoly of GDDR6X.

The bandwidth jump in real numbers

Memory bandwidth is the product of per-pin speed × bus width. GDDR7 raises the speed; bus width is set by the GPU die. Here's how it shakes out across the RTX 50 stack:

The 5090 number is the headline — 78% more memory bandwidth than the 4090 on a card already overkill for any gaming workload. But the more important figure is the 5070: 672 GB/s on a 192-bit bus. The RTX 4070 had 504 GB/s on the same bus width. That's a 33% bandwidth uplift on a mid-range card without expanding the memory bus — exactly what mainstream gamers needed.

The RTX 50 series — first GDDR7 generation

NVIDIA was first to GDDR7 by a wide margin. The Blackwell-based RTX 50 series shipped with GDDR7 across every consumer SKU, and SA pricing has stabilised through mid-2026:

The mid-range positioning is the interesting story. The RTX 5070 with 12GB GDDR7 lands roughly where the 4070 Super sat in real-world performance — but with significantly more headroom for ray tracing and high-resolution texture work. The 5060 Ti's 8GB variant ships specifically because GDDR7's bandwidth makes 8GB workable at 1080p/1440p in a way GDDR6's 8GB couldn't be.

Looking forward, NVIDIA's Rubin architecture (expected late 2026 / early 2027) will pair GDDR7 with HBM4 — HBM4 on the flagship compute SKUs, GDDR7 on consumer and prosumer inference cards. Speeds should push toward the 36 Gbps tier by Rubin launch, taking the equivalent 5090-class card past 2,000 GB/s.

Why bandwidth matters for ray tracing and 4K

Traditional rasterisation is bandwidth-friendly. The GPU walks through geometry in a predictable order, pulls textures coherently, and writes to a frame buffer linearly. Caches help enormously. GDDR6 was fast enough.

Ray tracing breaks all of that. Rays bounce in unpredictable directions, hit incoherent texture and material data, traverse BVH (bounding volume hierarchy) structures scattered across memory, and generate access patterns that don't fit cleanly into any cache. The GPU spends a much larger fraction of its time waiting for memory to return data.

Path tracing is worse still. Cyberpunk 2077 with path tracing enabled, Alan Wake 2 with full RT, Black Myth: Wukong at 4K — these workloads can saturate GDDR6X bandwidth on a 4090. The card has compute headroom it can't use because memory can't feed it fast enough.

GDDR7 directly addresses this. The 78% bandwidth uplift on the 5090 translates to roughly 25-40% real-world uplift in path-traced workloads — measurably more than the raw shader-count improvement would predict. The bottleneck moved.

Power, voltage and thermal advantages

The voltage drop from 1.35V (GDDR6X) to 1.1V (GDDR7) is the single biggest power saving. Combined with PAM3's lower power-per-bit profile, the entire memory subsystem on an RTX 5080 draws less power than the GDDR6X subsystem on an RTX 4080 — despite delivering more bandwidth.

Real numbers from board-partner thermal testing:

• Memory junction temps drop 10-15°C at equivalent fan speeds on RTX 50 cards versus their RTX 40 predecessors.
• VRM load on the memory rails is roughly 18% lower — meaning cheaper memory VRM designs are viable on cost-down board partner SKUs.
• Per-card memory power consumption is roughly 15-25W on a 5070, 25-35W on a 5080, around 50-65W on a 5090 — down from 35-90W on the equivalent RTX 40 tier.

The RTX 4090's notoriously hot GDDR6X (regularly 95-100°C memory junction) is the cautionary tale this generation avoided. The 5090 ships with memory running 75-85°C under the same workload — comfortable territory.

Supply chain and pricing — Samsung, SK Hynix, Micron

Three major DRAM suppliers shipping GDDR7 is a huge structural improvement over GDDR6X (Micron-only). Competition keeps pricing honest. Here's the supply picture as of mid-2026:

Samsung hit volume production first, late 2024, with the K4VAF325ZC 16Gb modules. They're the primary supplier to NVIDIA's RTX 50 series and dominate consumer card BOMs.

SK Hynix followed in Q2 2025 with the HKMG7QQ4-32B parts. They're heavily weighted to NVIDIA datacenter and AI inference SKUs, with consumer allocation increasing through 2026.

Micron arrived last (Q4 2025) but brought the densest modules — including early 24Gb samples that show up on professional / workstation cards before consumer.

Looking forward, the supply expansion in late 2026 (Samsung's Pyeongtaek P4 line and Micron's Hiroshima fab) should drop GDDR7 pricing premiums significantly. Expect GDDR7 to be at price parity with GDDR6 by Q4 2027, after which there's no reason for any new GPU launch to use GDDR6 outside of true entry-level.

Key takeaways

1. GDDR7 launches at 32 Gbps per pin — 50%+ faster than GDDR6X, with roadmap targets at 36-40 Gbps.
2. PAM3 signalling is the smart compromise — cleaner integrity, lower power, and three-supplier competition.
3. RTX 5090 gains 78% bandwidth over the 4090 — biggest single-generation jump since GDDR5 to GDDR5X.
4. Path tracing and 4K RT workloads benefit most — sometimes 25-40% real-world uplift from bandwidth alone.
5. Memory power is down 20-30% per bit — cards run cooler, cheaper PCBs are viable, no more 100°C VRAM.

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