The Federal Reserve's hawkish stance to control surging inflation by increasing interest rates has weighed heavily on growth stocks this year, with investors deciding to dump high-growth companies despite some impressive financial results.

Advanced Micro Devices (AMD -2.94%) and Fortinet (FTNT 1.02%) are two such growth stocks that have borne the brunt of the market sell-off. While AMD stock is down nearly 60% in 2022, Fortinet has lost 28% of its value so far. The substantial pullback in these stocks means that investors now have an opportunity to buy them at relatively cheap valuations. Let's look at the reasons why they may want to buy shares of these two red-hot growth stocks while they are still down in 2022.

1. Advanced Micro Devices

Buying AMD stock right now is a no-brainer for two reasons.

First, the stock now trades at a mouthwatering valuation and looks like a value play when we consider its impressive growth. AMD sports a trailing price-to-earnings (P/E) ratio of 25, which is substantially lower than its five-year average P/E ratio of 100. The forward P/E ratio of 12 shows that analysts expect a big spike in AMD's earnings over the next year.

Throw in a price-to-sales ratio of 3.7, which is lower than the five-year average sales multiple of 6.9, and it is easy to see why AMD stock is worth buying following its steep decline in 2022.

The second reason why you may want to buy AMD is that it is set to grow impressively despite the headwinds in the personal computer (PC) market it is facing right now. The company recently released preliminary Q3 results that turned out to be disappointing. It lowered its revenue estimate by $1.1 billion to $5.6 billion for the quarter, blaming a weak PC market that wrecked the demand for its processors. While such a huge cut is alarming, AMD is still on track to report 29% year-over-year revenue growth for the third quarter thanks to its diversified end markets.

Xilinx's acquisition, growth in data centers, and resilient gaming business should help AMD mitigate the weakness in the PC space. These growth drivers are long-term in nature. The server processor market, for instance, presents a $42 billion opportunity for AMD to dig into. The chipmaker is still a small player in this space with a market share of 13.9% in the second quarter, but it has been gaining ground steadily over the past few years.

AMD looks set for more market share gains over the next three years in this space thanks to delays in the launch of new server processors by rival Intel and the execution issues that the latter is facing. The demand for gaming consoles is going to be another key catalyst for AMD, as the company's semi-custom chips power devices from Sony, Microsoft, and Valve.

Sales of gaming consoles such as the PlayStation 5 and the Xbox Series S and Series X are expected to increase substantially over the next five years. This should bode well for AMD's gaming business, which has defied the weakness in the GPU (graphics processing unit) space thanks to the console market.

As it turns out, AMD's gaming segment grew 14% year over year in the second quarter to $1.6 billion in revenue despite a drop in sales of graphics cards. So AMD has multiple catalysts to ensure robust long-term growth. Analysts also think the same, and expect AMD's earnings to clock an annual growth rate of 26% for the next five years, which means investors are getting a great opportunity to buy this high-growth tech stock on the cheap right now.

2. Fortinet

Fortinet stock trades at 63 times trailing earnings following its decline this year. While that's not cheap, it is worth noting that the cybersecurity specialist traded at an expensive 108 times earnings last year. What's more, a forward P/E multiple of 40 suggests that Fortinet's earnings are set to increase over the next year.

The rich valuation means that the stock could head lower if the market sell-off intensifies, but that could give investors a better entry point into Fortinet. Savvy investors may not want to miss such an opportunity given Fortinet's eye-popping growth and sunny prospects.

The company's revenue increased 29% in the first six months of 2022 to $1.98 billion. More importantly, the pace of growth in Fortinet's deferred revenue points toward a brighter future. The company's deferred revenue shot up 35% year over year in the second quarter to $3.93 billion. Deferred revenue is the money collected in advance by a company for services that will be delivered later.

The fact that this metric grew at a faster pace than the actual revenue indicates that Fortinet built a solid sales pipeline. It is also worth noting that the company's deferred revenue is greater than its trailing 12-month revenue of $3.8 billion, suggesting that its top-line momentum is here to stay.

Moreover, the massive end-market opportunity Fortinet sits on should allow the company to maintain healthy levels of growth for a long time. The company sees a total addressable revenue opportunity worth $199 billion in the cybersecurity space by 2026, so it is scratching the surface of a massive market.

Additionally, Fortinet's solid market share in fast-growing cybersecurity niches such as firewalls should help it corner a nice chunk of the huge revenue opportunity it is sitting on. The company had a 37% share of the firewall appliances market in 2021, and it led the market by a big margin over competitors such as Cisco, Palo Alto Networks, and Check Point Software.

As such, it is not surprising to see that analysts anticipate 23%-plus annual earnings growth from Fortinet. That's why any dips in Fortinet stock amid the ongoing sell-off can be considered as an opportunity to buy shares of this cybersecurity specialist that could deliver a nice upside in the long run.