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Two black low-profile DDR5 modules with matte aluminum heatspreaders

G.SKILL

G.SKILL F5-6400J3644F64GX2-RS5K 128GB (2×64GB) DDR5 6400 CL36 desktop RAM

SKU CH-JPYM-2PYAX MPN F5-6400J3644F64GX2-RS5K

128 GB dual-channel DDR5 kit at 6400 MT/s with CL36 timings and a 33 mm low-profile heat spreader

  • Total capacity128 GB (2 × 64 GB)
  • Rated speedDDR5 6400 (PC5 51200)
  • CAS latencyCL36
  • Memory timings36-44-44-102
  • Rated voltage1.35 V
  • Kit configurationDual Channel Kit
  • 128GB capacity supports heavy multitasking and large datasets
  • 6400 MT/s data rate delivers high memory bandwidth
  • CL36 latency with 36-44-44-102 timings balances speed and responsiveness
  • 33mm low-profile height clears large CPU coolers
  • Intel XMP 3.0 profile enables one-click overclocking

Ripjaws S5 128GB DDR5 Kit

This 128GB kit contains two 64GB DDR5 modules rated at 6400 MT/s with CL36 timing. The low-profile 33mm height suits compact builds and large CPU coolers. Hand-screened ICs and Intel XMP 3.0 support target enthusiasts and gamers on compatible Intel 600, 700 and 800 series platforms.

Thermals and Power at 1.35V

Aluminum heatspreaders on each module move heat away from the hand-screened ICs during sustained workloads. The 1.35V operating voltage keeps power draw modest for a DDR5-6400 kit. No onboard LEDs mean zero extra lighting power or software control overhead.

What XMP 3.0 Changes

Enabling the Intel XMP 3.0 profile in BIOS automatically sets 6400 MT/s, 36-44-44-102 timings and 1.35V without manual tuning. The dual-channel 2×64GB configuration delivers 128GB total capacity for memory-intensive tasks. No additional software or drivers are required beyond the motherboard firmware.

How it compares

Measured against everything we stock in Desktop RAM, at today’s prices. Recalculated every night.

Price $2,457.99
Pricier than about 90% of the 3,647 comparable items (median $90.99).
Total capacity 128 GB (2 × 64 GB)
Higher than about 93% of the 3,251 comparable items (median 16 GB).
Price per GB $19.20 per GB
Pricier than about 90% of the 3,251 comparable items (median $6.75 per GB).

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Specifications

Product
Brand nameG.SKILL
Product lineRipjaws S5 Series
Model nameF5-6400J3644F64GX2-RS5K
Total capacity128 GB (2 × 64 GB)
Product type288-Pin PC RAM
Product colorBlack
Performance
Rated speedDDR5 6400 (PC5 51200)
Memory
CAS latencyCL36
Memory timings36-44-44-102
Kit configurationDual Channel Kit
Memory profilesIntel XMP 3.0
Heat spreaderYes
Power
Rated voltage1.35 V
Size & build
Shipping weight0.14 kg
Package size229 × 152 × 19 mm
Compatibility
Recommended forHigh Performance or Gaming Memory / Intel 600 Series / Intel 700 Series / Intel 800 Series / Intel B660 / Intel B670 / Intel B760 / Intel Compatible / Intel Z690 / Intel Z790 / Intel Z890
More details
LED lightingNone

Questions about this item

How do I install the 288-pin DDR5 modules in the correct dual-channel slots and what step is commonly missed?

Align the notch on each 288-pin module with the slot key, press firmly until the retention clips click, then enable the Intel XMP 3.0 profile in BIOS so the kit runs at DDR5 6400 CL36 instead of the default JEDEC speed.

What maintenance will the Ripjaws S5 heatspreaders and memory ICs need over time?

The low-profile 33 mm aluminum heatspreaders are passive; periodically remove dust with compressed air to maintain thermal performance — no liquid cooling, thermal paste replacement or IC servicing is required.

What limit appears first when the 128 GB kit runs sustained workloads at 1.35 V?

The primary limit is thermal — the 33 mm heatspreaders rely on case airflow, so prolonged heavy loads can throttle speeds if chassis ventilation is insufficient.

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