Better Quantum Computing Stock: Nvidia vs. IonQ

On Wednesday, Nvidia (NASDAQ: NVDA) revealed that it has chosen IonQ's (NYSE: IONQ) Superion 256 system as the first quantum computer to be installed at the Nvidia Accelerated Quantum Research Center. IonQ is a pure-play quantum computing start-up, so this deal lends its systems legitimacy while helping Nvidia expand its footprint in the quantum computing space.

In light of this news, investors may wonder which of these two is the better quantum computing stock to invest in. The choice may come down to your personal investing tolerances. Here's why.

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The case for Nvidia

It is hard to argue against owning Nvidia stock. As most investors know, the GPU maker dominates the rapidly growing AI accelerator industry, and its data center chips have almost single-handedly transformed it into a tech behemoth.

The company now holds about $99 billion in liquidity. With that, it has begun to leverage its AI accelerator success into other product lines, and quantum computing is one of those areas.

At the research center, IonQ's Superion 256 will be connected to a cluster of Nvidia-powered servers using the NVQLink platform. IonQ's hardware will handle the quantum-specific tasks, while other processing-heavy workloads will be assigned to Nvidia's GB200 GPUs, with the whole system managed by Nvidia's CUDA-Q software.

Although it's still a stretch to refer to Nvidia as a "quantum computing company," the agreement with IonQ probably goes a long way toward showing how it's positioning itself for a quantum-oriented future.

For now, Nvidia remains primarily focused on AI. In the first half of its fiscal 2027 (which ended July 26), its revenue rose by 96% year over year to $178 billion. Also, due to the relatively slower growth in its costs and expenses, its net income surged by 161% to $118 billion.

While that increase was occurring, the stock rose by a more modest 22% over the last year, though it now carries a $5.4 trillion market cap. Also, it trades at a price-to-earnings ratio of 28 and a price-to-sales ratio of 18 times, despite its ongoing rapid growth in a market that it dominates. Though these profits did not come from quantum computing, Nvidia is an excellent and safe choice that also offers investors relatively rapid growth.

Why some investors might consider IonQ

IonQ does not have the luxury of making moves to diversify its revenue base, and its more modest $16 billion market cap reflects its status as a pure-play quantum computing company that is not yet profitable.

The future of such companies is usually uncertain at this stage. It is likely that many quantum computing companies will not succeed.

However, the odds of IonQ's success just rose significantly with this Nvidia deal. It introduced the Superion 256, its sixth-generation trapped-ion quantum computer, on Sept. 8. As its name reflects, it is built around 256 trapped-ion qubits, and it uses the same tech with which the company achieved 99.99% 2-gate fidelity in lab testing. These features make it both fast and -- relative to the machines produced by its rivals -- more accurate.

Additionally, the quantum computing chips it uses were fabricated on traditional semiconductor lines, making them manufacturable on a mass scale. That's likely another feature that made the Superion 256 attractive to Nvidia.

Unfortunately, IonQ has the financials of a struggling start-up. Its revenue of $145 million in the first half of 2026 far surpassed the $28 million it booked in the prior-year period. Still, it lost close to $1.1 billion in the first two quarters of this year, well above its $210 million loss in the same period last year.

IonQ has over $2.1 billion in liquidity, so it can sustain this pace of cash burning for now. Nonetheless, the company's struggles seem to have contributed to the stock's 40% decline over the last year. Furthermore, its price-to-sales (P/S) ratio of 61 shows that its valuation remains well ahead of the business's fundamentals, which makes buying the stock now risky.

Should investors choose Nvidia or IonQ?

Under current conditions, Nvidia is probably the more suitable choice for most investors.

Quantum computing is likely not yet a significant revenue source for Nvidia. Moreover, IonQ's new status as an Nvidia partner gives it a legitimacy that its most direct competitors may not currently have.

However, Nvidia offers rapid revenue and earnings growth at a comparatively low valuation. That makes it a safe bet for an investment that can surpass the market's performance.

In contrast, IonQ remains a highly speculative stock. Admittedly, eye-popping gains like the ones made from Nvidia's 1999 IPO sometimes make speculative stocks worthwhile. Should IonQ become a profitable quantum computing leader, the stock could deliver massive gains.

Still, such stocks are beyond the risk tolerances of most investors. Unless you have a huge appetite for risk, Nvidia is likely to be the more appropriate choice.

Will Healy has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends IonQ and Nvidia. The Motley Fool has a disclosure policy.