Sales of PC graphics add-in cards rose in the second quarter for the first time in nearly a decade, benefiting Nvidia and Advanced Micro Devices (AMD).

Add-in cards are for personal computers that are typically used by gamers, workstations, rendering farms and enterprise segments that need high-performance graphics. Based on data from Jon Peddie Research (JPR), add-in card sales jumped 30.9% in the second quarter from the first quarter, and 34.9% from a year earlier.

More than $3.6 billion of add-in hardware was sold last quarter, representing an increase of about $850 million over the first three months of the year. Nvidia NVDA, -1.61% and AMD AMD, -2.22% (and their board partners) are the only graphics-processor providers in the field.

Graphics cards and graphics processing units (GPUs) from AMD and Nvidia have seen projected sales increases over the past few months because of the rise of the cryptocurrency market. Bitcoin and Ethereum miners use the hardware to earn, find and verify transactions at an accelerated rate. Potential buyers in all market segments have been plagued by graphics card shortages and price increases in recent months because of the demand for coin-mining hardware. We now have sales numbers to put in context why that’s the case.

Read:Intel, once a sleeping giant, readies for battle with AMD and Qualcomm

Sales of add-in cards of AMD and Nvidia hardware were 520,000 units higher in the second quarter compared with the first quarter, according to JPR. Traditionally, we would expect the standard seasonal drop of 10,000-20,000 units. This indicates that upwards of 500,000 total units of high-end graphics were sold into the channel and, indeed, for mining-specific uses. About one in three graphics cards sold at retail, to OEMs or businesses was used for cryptocurrency mining.

Along with these sales numbers comes a market share shift. AMD Radeon graphics cards are better at cryptocurrency-mining workloads than Nvidia’s GeForce family, and miners targeted the AMD parts first. AMD gained nearly 2 percentage points of share (27.5% to 29.4%), while Nvidia dropped from 72.5% to 70.6% quarter to quarter.

The growth in add-in card sales is even more impressive when compared with the second-quarter’s 30%-plus drop in unit sales of desktop PCs.

Though the primary PC segment has declined dramatically, the discrete graphics space rose by 34.9%.

Also read:AMD finally re-enters high-end markets, taking aim at Intel and Nvidia

What remains to be seen is if this increase in GPU sales is sustainable for AMD and Nvidia, and if it will lead to more market-share shifts in AMD’s favor. We have already seen a leveling of the growth of Ethereum mining, but price changes and performance shifts in the graphics landscape have the potential to redirect it at any point.

The Nvidia product line remains better placed for the gaming landscape, and AMD has struggled with its release of a new architecture, code-named Vega. AMD benefits more from the continued strength of coin mining as it hides any potential deficiencies in the gaming segment.

Now read:Nvidia is more bullish on cryptocurrency than AMD

Ryan Shrout is the founder and lead analyst at Shrout Research, and the owner of PC Perspective. Follow him on Twitter @ryanshrout.